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BARC/1991/P/003
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SPECTROSCOPY DIVISIONPROGRESS REPORT FOR 1990
Edited byA. Sharma and S. M. Marathe
1991
BARC/1991/P/OO3
GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION
oo
oK
SPECTROSCOPY DIVISION
PROGRESS REPORT FOR 1990
Edited by
A. Sharma and S.M. Marathe
BHABHA ATOMIC RESEARCH CENTREBOMBAY, INDIA
1991
BARC/1991/P/003
BIBLIOGRAPHIC DESCRIPTION SHEET FOR TECHNICAL REPORT
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10 Title and subtitle : Spectroscopy Division i progressreport for 1990
11 Collation :
13 Project No. :
20 Personal author(s) :
196 p., figs., tabs.
A. Sharma; S.M. Marathe <«ds.)
21 Affiliation of author(s) :Spectroscopy Division, Bhabha AtomicResearch Centre, Bombay
22 Corporate author(s) : Bhabha Atomic Research Centre,Bombay - 400 085
23 Originating unit : Spectroscopy Division, BARC, Bombay
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Department of Atomic Energy
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August 1991
September 1991
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6(2 Abstract : This report summeri ses the work done by members ofthe Spectroscopy Division both within BARC as well as inscientific insfcitutiens elsewhere during the calendar year 1990.Main tHruas of research activity include atomic spectroscopy forhyperfine structure and isotcpe shift determi nation, theoreticaland e?>;per imnnta 1 studies c-f diatomic molecules, infrared andRaman opectroc.copy of polyatomic molecules, design andfabrication of be,?m line optics for INDUS-1 synchrotronradiation source?, beam fail spectrascopy and laser spectroscopyof various atomic and molecular systems. Major experimentalfacilities that have been utilised include a fourier transformspectrometer, i\n c>>:cimer la^or pumpsd dye-laser and a continuouswave argon—ion laser. The report also includes thecpLctrcscapic analytical cervici; rendered fur vdr ious DAE unitsand de-scribes briefly some new analytical facilities like la&erenhenc3d i on i 2 r>, h i on in f lamas and resonance ionization massspectroECopy using pulsed lasers which are being set up. The?above activities were reported by members of the SpectroscopyDivision via invited lectures, p spurs presented in variousnational and international conferences and publication inscientific journals. Details of these are given at the end ofthe report.
70 Keyi-srdsi/Descriptors : PROGRESS REPORT; EMISSION SPECTROSCOPY;X-r-:AY FLUORESCENCE ANALYSIS; TRACE AMOUNTS; INFRARED SPECTRA;RAKAN SPECTRA; RESEARCH PRDi^AMB; LASER SPECTROSCDPY;ROTATIONAL STATES; DARC; THIN FILMS; VIBRATIONAL STATES;MOLECULAR STRUCTURE
71 Class No. : INI Subjact Category : A12.10; B11.20
99 Supplementary elements : The previous progress report coveringthe..- period January 1989-Dscember 1989was published as BARC—1536.
C O N T E N T S
ANALYSIS BY OPTICAL EMISSION SPECTROSCOPY
1.1 INDUCTIVELY COOPLEI) PLASMA-ATOMIC EMISSION SPECTROMETRT(ICP-AES)
1.1.1 Determination of adjacent rare earths in high purityby ICP-AES 1
1.1.2 Determination of Aluminium in Niobium by ICP-AES 3
1.2 SERVICE ANALYSIS 4
2. ATOMIC, MOLECULAR, SOLID STATE AND LASER SPECTROSCOFY
2.1 ATOMIC SPECTRA
2.1.1 Isotope shift studies in levels of 4^50*63 and 4f<*5d6pconfiguration of Sml and confirmation of aoae tentativeassignments. 6
2.1.2 Term Dependence of Isotope Shift3 in the 4fv5d26sconfiguration of neutral Gadolinium 9
2.1.3 Term shifts in odd and even parity levels and theirvariation in JiLn coupled states of 4f* 5d6sconfiguration of Yb* 11
2.1.4 Esti mation of Gaussian and Lorentzian width byDeconvolution of Airy Line Shape 15
2 . 2 SODD STATE SPECTRA
2.2.1 6-d Luminescence in O**:ThBr4 18
2.3 ELECTRONIC SPECTRA AND STRUCTURE OF SIMPLE MOLECULES
2.3.1 On the Determination of Vibration Transition Dlpole Monontfrom Rovibrational Intensities: Application to CIO and 19HC1 as Test Cases.
2.3.2 Rotation-Vibration Spectrum of Oxygen Moleculo: Estimationof Magnetic Dipole Contribution to Intensity. 22
2.3.3 Aspects of Forbidden Transitions in Diatomic Spectra:Line Intensities in Intra-Multiplet Transitions. 25
2.3.4 The Vibrational and Rotational Analysis of tho A*n
Bands of SiSe 28
2.3.5 The Electronic Spectrum of Silicon Monotelluride (SIT©) 34
2.3.6 Broad band emission spectrum of InBr at 52(5 nm. 37
2.3.7 Absorption Spectrum of InBr 38
2.3.8 Spectrum of Hfia 39
2.3.9 The 430 nm System of Indium Oxide 40
2.3.10 The spectrum of the InO* molecule 46
2.3.11 The spectrum of InCl* 50
2.4 INFRARED AND RAMAN SPECTRA
2.4.1 Low Temperature and Long path Multiple Reflection set upfor diode laser and FTIR instruments. 54
2.4.2 Fourier Transform High Resolution study of 2i>j> band ofGD3CGH 58
2.4.3 Perturbations in the v7 state of CDgCCH 61
2.4.4 Perturbations in the vibration-rotational hot bands ofacetylene in the 2650-4100 cm" region. 66
2.4.5 High Resolution FTIR spectra of propyne-d in 9-11 MMregion 68
2.4.6 High Resolution Infrared Spectroscoplc measurements withthe Bomem DA3.002 Fourier Transform Spectrometer 70
2.4.7 Infrared and Raman Spectroscopic Studies of high-TeSuperconductors & Related Materials 74
2.4.8 Double Resonance Study of Nil, with TEA CGfe Laser and DiodeLaser 80
2.5 LASER SFECTROSCOPY
2.5.1 Determination of Dltratrace Levels of Deuterium and 81Tritium in EfeO
2.5.2 High Fressure Studies of Compounds using Laser RamanSpectrometer 82
2.5.3 Plasmei emission characteristics of laser ablated 3olids 86
2.5.4 Formation of thin films by laser ablation of high T(.superconducting materials. 88
2.5.5 Pulsed Laser induced hole burning in an aerosol medium: Anew technique for flow visualization in gases. 89
2.5.6 Detection of Sub-PicoKram Concentrations of Sodium byOne-Step Laser Enhanced Ionisation Spectrometry 96
2.5.7 Effect of Laser Power on LEI Signal of One-photon andTwo-Photon Lines of Sodium 100
2.5.8 Effect of Low and High Ionisation Potential Elements onLaser Enhanced Ionisation Signal of Sodium 105
2.5.9 Molecular Photophysics 108
2.5.10 Two Poton Spectroscopy of Autoionising Levels of SingletSulphur (3*50) 111
2.5.11 (2+1) REMPI Spectroscopy of Excited O 1 ^ ) Sulphur Atom 118
2.5.12 Laser power dependent studies in Multiphoton ionisationof Ba 123
2.5.13 Study of Roll of Collisions in Multiphoton Ionisation ofBa 126
2.5.14 Setting of a Resonance Ioniaation Mass SpectrometryFacility for the Ultra trace Detection of short-lived 129isotopes.
2.6 SYNCHROTRON, BEAM-FOIL AND PLASMA SPECTROSCOPY
2.6.1 Progress report on the beam line for PES of solids andgasos in INDUS-I 132
2.6.2 High Resolution VUV Spectroscopic Facility at INDUS-I 135
2.6.3 Design and evaluation of PES Beamline Optics 145
2.6.4 Design and evaluation of High Resolution VUV DoaralineOptics 151
2.6.5 Beam-Foil Spectroscope 155
2.6.6 Reinvestigation of some of the autoionizing lines of Cul 160
3. ELECTRONICS
3.1.1 Signal Detection and Processing for ICP Spectrometer 165
3.1.2 Instruments Maintained and Serviced 169
4. FABRICATION AND MACHINE SHOP ACTIVITIES
4.1.1 Interfacing of Recording Fabry-Perot Spectrometer withPersonal Computer • 170
4.1.2 Machine Shop Activities 171
5. POBLICATIONS
5.1 Papers published in scientific journals 179
5.2 BARC Reports 180
5.3 Papers presented in Conferences, Symposia, Seminars etc. 181
5.4 Invited talks 184
6. OTHER ACADEMIC ACTIVITIES
6.1 Members registered for M.Sc/Ph.D degrees 187
DIVISIONAL STAFF CHART 189
.1 —1 . 1 . 1
DETERMINATION OF ADJACENT RARE EARTHS W HIGH PURITV E U 2 0 . BV
ICP-AESS.S. Bisnas, I.J. Machado *nd P.S. Marty
High purity Ei^O, was analysed for Pr, Nd, Sm, Gd, Tb and
Dy by ICF'-AES. Samples containing 1 ing/ml of Eu were nebulized
into the plarma generated by a 56 MHz R.F. generator delivering m
•forward power of 1.3 KW. Calibration standards containing th«
above six rare earths in the concentration range 0.05-1.0 ^ig/ml
with 1 mg/ml of Eu were used. Scanning of the analyte lines
chosen for calibration was done by Jobin-Yvon lm-Czerny-Turn»r
monochromator (Model no. JY-38 THR 10130). The analytical data is
given in Table 1. In Table 2, the lowest quantitatively
determinable (LQD) concentrations obtained by the present method
are compared with those of OES and XRF methods previously
employed in our laboratory.
Table Is Analyte wavelengths and detection limits
ElementWavelength
Pr 422.293
NtJ 406. 109
Sm 446.734
Gd 303.284
Tb 370.392
Dy 364.540
Detectionaqueoussolution
<ng/ml)
28
8
8
7
20
8
Limits*matrixsolution
(ng/ml>
38
18
15
15
45
30
RSDb
<7.)
7.5
2.7
3.4
3.5
1.6
2.0
"Calculated using the method given in Ref.1
for the RE concentration range 0.05-1.0 fjg/ml
^
Table 2: Comparison o-f LQD Concentrations
Element LQD l{jg/g)
ICP-AES* OESb
Pr
Nd
Sm
Ed
Tb
Dy
50
100
50
513
100
100
50
80
50
150
60
100
200
100
50
100
200
"Present Work
cfrom Re-f.3
References:1. R.K. Winge, V.J. Peterson and V.A. Fassel, Appl.
Spectrosc., 33, 206 <1979).
2. P.S. Murty and S.M. Marathe, Z. Anal. Chem., 272, 341U974)
3. R.M. Dixit and S.S. Deshpande, BARC Report No. 1275, 1985.
3 -
1.1.2
DETERMINATION or AmMtNturt ttt NIOBIUM BV JCP-AES
P.S. Hurty *nd B.K. Ankush
A preliminary method was developed for the determination of
Al in niobium by ICP-AES. Niobium sample was dissolved in
aquaregia and HF and the solution containing lmg/ml of Nb was
used -fur- ICP analysis. Al 396.. 152n<n lino Mas scanned on a
monochroniator (Model No. JY-?B THR K36N9) using aqueous standards
for calibration. Using this method Al at More than 0.IX could be
determined in Nb. The average background intensity adjacent to
Al 396.152 nn line in Nb matrix, was enhanced by a factor of
about i.S compared to the background intensity frr aqueous
standards. Due to this difference in background, it aay be
necessary to enploy matrix matched standards -for calibration.
This is being investigated.
1.2
SERVICE ANALYSIS
S.H. Marathe
Our Division has been regularly carrying out analysis of
Uranium and a wide range of other materials. The table shows
break-up of analysis of samples carried out in 1996) received from
different divisions of BARC and from other units of DAE.
The ICP Spectrometer installed in 1987 is now being
regularly employed in the plasma mode to analyse rara earth
materials like LagO,, T^O,, Go^O,, Eu20,, Dy20, and Y208 for
traces of other rare earths. Rare-earths separated from Uranium
by solvent extraction by the UMP are now analysed in the plasma
mode. Previously these were being separated by column extraction
and caprecipitation analysed spectrographically. Uranium (as
U30a) samples are analysed for B, Cd etc., in the DC arc mode on
the same spectrometer.
Steel and stainless steel samples are analysed by Spark
emission for C,S,P etc., on the Direct Reading Spectrometer.
Other types of samples ware analysed spectrographically, using DC
arc excitation.
- 5 -••
Break up of Service Analysis carrl«tl out in 1990
Baurcm Type of Samples No. ofSamp lei
No. ofdeterminationi
A> BARC Units
UMP
(UED)
AFD
RE oxides, UF4,
Mg, RE nitrate
Y20gV DM water, U-ore,
Calcium nitrate,
carbon, graphite.
U, Stainless steel,
Carbon steel.
720
390
3588
2684
Metal- Y-Ba-Cu-D, Al-Zr t
lurgy SnO2, stainless
WD9J1 Cu, V, Sn, NiO.
Other Stainless Steel,
Units o-f SnDj,, RE Oxide, Ti,
BARC Graphite powder,
Ag-Cu alloy, BaC09,
CuO, Y203,
B80.
59 314
36 220
B) DAEIRE(Udyog-
mandal>
NPC
CAT
UnitsY20a, EUjsQa, Bd^O,
Trichromatic
phosphor.
Carbon steel
Stainless steel
17 92
3
3
Total 1224 6904
Chemistry Division, Chem. Engg. Division, NtPD, Chemical Engg.Group, Powder Metallurgy Division, Applied Chemistry Division,TP&PED.
2.1.1
ISOTOPE SHIFT STUDIES IN LEVELS OF 4FS5D*6S AND 4-F^5D6PCONFIGURATION OF S M I AND CONFIRMATION OF SOME TENTATIVEASSIGNMENTS.
S.H. Afzal, S.G. Hakhate, Pushpa Rao, A. Venugopalan, S.A. Ahmadmnd G.D. Saksena
The configurations 4fB5dz6s and 4f<s5d6p have baen
tentatively assigned earlier C13 to a -few energy levels of
neutral samarium atom (SmI) and isotope shift or theoretical
studies which could confirm these level assignments, have not
been reported so far. Isotope shift ( Sm - Sm> have been
measured presently in transitions involving some of these levels
tentatively assigned. The tentative assignment ClD of 4f 5d 6»
configuration to some of the levels of Sm are confirmed or* the
basis of the present isotope shift studies. Ten transitions of
the type 4f 5d 6s — 4f 6s showed nearly zero IS. This is
expected, for the change in the electron charge density A|f><0) |
at the nucleus during the transition 4f 5d 6s — 4f 6s is
negligible. A -fow lDvot-es-^oiyneJ lu <tftf£)B2 is—negligible, A
few levels assigned to 4ftfSd6p are not pure and there is some
configuration mixing as is evident from the small value of IS for
4f*5d6p - 4f**6s2 transitions(^\Tbe levels belonging to 4f*5d*6s
configuration whi-ch have been confirmed from the present studies
along with levels belonging to 4f*5d6p« are- shown—i**-—Fig.4-.
Assuming a level shift of Xmk in the level at 0.0 belonging to
4f 6s configuration, the term shifts are evaluated. The levels
belonging to 4ftfSd6p configuration exhibit configuration mixing
and the extent of mixing has to be evaluated, for which
additional studies are taken up. Further studies Otf€ in progress.
-7--
Reference:
1. W.V. Martin, R. Zalubas and L. Hagan, Atomic anargy 1avals
the rare-earth elements NSRDS-NBS 60 National Bureau of
Standards, Washington (1978).
- 9 -
(M.i.) ffj.
2.1.2
TERM DEPENDENCE OF ISOTOPE SHIFTS IN THE 4*'5d*6* CONFIGURATION
OF NEUTRAL GADOUNIUM
A. Vwnugopalan, S.A. Ahmad and G.U. Salcsena
In the first-order approximation, isotope shift IS [Specific
M^ss Shift (SMS) and Field Shift (FS) 1 in heavy elements t.as ton
same value for all terms of a pure configuration. Experimentally
it was found that FS (which is mainly predominant in h««vy
elements) were different for different terms of the sant
configuration. This has been explained as d.ie to the crossed
second-order (CSO) effect. The CSO ef feet causes a term
dependent FS as the terms of a pure configuration have vary
slightly different electronic charge densities |y(0>| at the
nucleus.
We have carried out extensive investigations to study the
term dependence of isotope shift in the 4f J>d 6s configuration of
neutral gadolinium. The IB in arious terms of 4f 5d 6s
configuration of Gdl have been evaluated by measuring IS in
several spectral lines involving transitions with 32 levels of
Gdl assigned to the 4f75d26s configuration. Highly enriched
isotopic samples *s<*Gd and '""Gd were used for these studies.
The experimental details are the same as in our earlier
publication C1J. The studies have yielded term shifts AT
(156-160) for eight terms of the 4f75d*6s configuration of Gdl,
given in Table 1. As could be seen, the four parental terms,
1OF, *F, 1OP and BD of the coreconf igur at ion 4f*5d2, commbin*
with the 6s electron causing the parent term to split into two
--Jo-
Russel-Saundors terms; eg. , the F parental term from
4f75dz<iOF) combining with 6s gives risa to 41F and *V terms and
similarly -for other parent terms.
Table 1: Term Shifts for various terms of the 4f 5a 6s
configuration of Bdl <lmk = lB^cm"1)
Term AT(156-16©) Term AT(156-160)
C4f75d2(1OF)6s,"FD 86 mK C4f 75dZ (1OF)6s,PF3 76 mK
C4f75d2(loF)6s,PFJ 68 mK C4f 75d2 (1°F)6s,11F3 65 mK
C4f75d2(loP)6s,"P3 88 mK C4f 75d2 (iOP)6s,PP3 76 mK
C4f75d2(8D)6s,PD3 70 mK C4f75d2(°D)6s,7D3 78 mK
The CSQ effect, which is due to the fai—off—configuration
mixing results in different values of |y(0)| for each of these
two terms arising out of the same parent term. AT, which is
proportional to |y(0)| , is thus different for these two terms.
No calculations are presently available for the |y((3)| values of
different terms of the 4f 5d 6s configuration of Gdl.
Hartree—Fock calculation is available for the |y((3)| values for
various ter.ns of the 5d 6s configuration of LaIC23 the trend of
variation in |y(0) | values of various LS terms of Lai are
similar to the ones observed presently in Gdl..
References
1. S.A. Ahmad, 6.D. Saksena and A. Venugopalan, Physica 81C,366 (1976).
2. M. Wilson, Phys. Rev. A3, 45 (1971).
-ii-
2.1.3
TERM SHFTS IN ODD AND EVEN PARITY LEVELS AND THEIR VARIATION W
J»Ln COUPLED STATES OF 4F*^5D6S CONFIGURATION OF YB*
Pushpa H. Rao, S.A. Ahmad and G.D. Saksana
Isotope shift studies by earlier workers in singly—ioni^sd
ytterbium (Yb*> are confined to only four lines, all of thorn
involving the ground state configuration 4f146s( and threa
transitions of the type 4f1<46p - 4f4<*6s were studied C13. This
did not not allow the evaluation of term isotope shifts (AT) for
the levels of Yb*, and for most of the levels the configuration
assignments exist [23. Theoretical calculation of most of tha
odd and even parity levels also exist C33 but so far evaluation
of term shifts (AT) of the levels of Yb% which could confirm th»
configuration assignments had not been made. The present studies
concern the measurement of IS in transitions in Yb* spectrum and
the evaluation of AT values for the levels of all the known
configurations of Yb*.
The IS studies were carried out in 32 spectral lines of Yb*
in highly enriched samples of Yb and Yb excited in liquid
nitrogen cooled hollow cathodes and using the recording
Fabry-Perot spectrometer with etalons coated for the UV ragion
(3200-4100A).
The term isotope shifts (AT) for the odd and even levels
were evaluated from the experimentally measured isotope shifts in
the transitions. The AT values for various configurations of Yb*
•valuated for the first time in the present studies are
summarised in Table 1. These AT values are compatible with the
•-12-
AT values of the odd and even configurations o-f neutral Yb atom
(Ybt)C43. This could be checked as most of the AT values of Yb
could be eva.. ted using the screening parameters and AT values
of various configurations of Yb .
The first example of JjLu coupling scheme was found in the
levels of 4f135d6s odd configuration of Yb* by Racah C53. Fro.n
the present studies we have attempted to check whether the levels
belonging to 4f135d6s electronic configuration could be grouped
according to their different JtLtl term designations. We have
found that the AT values of levels belong to CJ1Ltl3 arm
somewhat different from those levels of EJ1L113. This shows
that there is a small difference in |*>(fl) | values of the level
depending on their multiplicity M. That is, the term shifts AT
of levels 3Cll/23°, **C9/23° etc., of 4f19 <2FVy,z>5d6s<3D>
configurations are slightly larger than that for the levels
1Cll/23°, ^9/23° etch Df 4fi3 (2F7//2>5d6s(1D° ) configuration.
This observation is being reported for the first time in this
type of coupling scheme.
The term isotope shifts of levels belonging to the 4f* 5d6s
configuration is given belaw.
-JS-
Parity Configuration AT<172Yb - *7<*Yb>xl0 *ci»~*
Even 4f**6s S3 ± 2
4fi36s6p 145 ± 10
4f**7s 10 ± 3
4fi-*6d - 0
Odd 4f136s2 255 ± 1 0
4fi35d6s 145+20
4f**6p 10 ± 5
The configuration assignments of odd and even levels of
Yb , based on other experiments as well as theoretical
calculations are mostly confirmed by the AT C172Yb - 17<IYb) for
the odd parity level of 4f195cJ6s configuration at 38342.02 cm"1
is AT = 125 mk, which indicates a configuration mixing, as for a
pure 4f 5d6s configuration the value is 145 mk. The value of AT
for this level is not compatible with the configuration assigned
to it on the basis of the theoretical calculations in Table 2.
-14-
Table 2: Term shifts AT of energy levels belonging 4f**5d6s
configuration.
Level Configuration J Design AT(mk)
)5d6s(sDJ 5/2 "Cli3 153
ISO
148
1S1
145
145
*D) 11/2 *C5i3 124
125
References
1. A.R. Golovin and A.R. Striganov, Opt. and Spect. 19, 467(1965).
2. W.F. Megsprus, J. Research NBS (USA), 71A, 396 (1967).
3. W.V. Martin, R. Zalubas and L. Hagan, Atomic Energy Levelsthe rare earth elements NSRDS-NBS 60 National Bureaul ofStandards, Washington (1978).
4. S.A. AhmadT t.J. Machado and G.D. Saksena, Spectrochim A=ta35B 215 U9BQ).
5. G. Racah, J. Opt. Soc. Aram. 57, 771 (1960).
26759
28758
30224
30563
33495
35831
34785
38342
4f"
4f*8
5/2
3/2
9/2
11/2
7/2
11/2
11/2
9/2
2
"ciia
2
2
2
2
2
2
2.1.4
ESTIMATION OF GAUSSIAN AND LORENTZIAN WIDTH BY DECONVOLUTION OFAIRY LINE SHAPE
S.G. Nakhate,. S.A. Ahnad and G.O. Smksena
Spectral line shape at law densities, where impact
approximation is justified can be described by Voigt profile with
Lorentzilan half—width proportional to the atom density and the
Gaussian half-width corresponding to the temperature of the gas.
In Fabry-Derot (FP) interfwrometer the observed line profile is
described by Airy function which is the convolution of the Voigt
profile and the instrumental profile of the FP interferometer.
For the ideal FP interferometer the numerically convenient
expression for this convolution is given by Ballik* and it has
the form:
IT(z) = CF "*"n=t00 Z 2
C— + Z (Re ) e2 n=i
where IT(z) is the tr-ansmi tted intensity of a Fabry—P«rot
interferometer
R = Reflectivity of FP plates
L - riAvL AvL = Lorentzian full width at half maximum (FWHM)
, Ai>D >s: Gaussian FWHM
->j_ = Free spectral range a-f FP interferometer
= -m£• ( t is the distance between FP plates in cm)
-J i
i\ —» arbitrary relative -frequency -from the centre of
ths -fringe.
We have recorded the 3472.57A mercury line from a hoi1DM
cathode discharge lamp <HCL) on our recently converted digital
Recording Fabry-Perot Spectrometer (REFPQS). The recorded data
was fitted into equation (1) using least square fit method, and
the values of the parameters L and D were extractad. The digital
record of the 3472.57A Nel line on FP spectrometer along with tho
theoretically fitted curve is given in Figure 1. Using values of
these parameters, the Lorentzian and the Gaussian half width were
found to be 11.94 mk and 118.38 mk respectively. The FWHM vD «•
118.3B mk corresponds to a discharge temperature of 664.6°K (for
HCL current 40 mAmp.
The line shape studies of Ne, He excited in EDL and hollow
cathode discharge lamp are being undertaken to get a estimate of
temperatures with various emitters as well as to test th« valuas
of parameters evaluated above.
References:
1. E.A. Ballik, Applied Optics 5, 170 (1966).
8
o
- 1 8 -
2.2.1
6 - D LUMINESCENCE IN U**:TH8R«
R.C. Naik and J.C. Krupa
Though U4* ion in Thl5r4(1>, ThCl4 and in several
crystalline solids '' has extensively bean studied and many
of the energy levels of its ground 5f configuration have been
located experimentally, the excited Sf 6d configuration has so
far eluded the experimental observation. In this communication
we report broad band luminescence observed for the first time in
U * in the near ultraviolet region. These luminescence bands arm
attributed to 5fi6d1 • 5f* transitions of U** ion. The
excitation spectra of 6d and also 5f luminescence showed that th«
5f 6d configuration has absorption bands extending from 4400A
upto to 2600A. Excitation into the 6d levels of U * gives strong
fluorescence from the 5f levels suggesting very effective
non-radiative relaxation from 6d > 5f .levels suggesting very
effective non—radiative relaxation from 6d — • 5f levels of U
under favourable conditions, 6d luminescence is quenched with
higher U concentration.
References:
1. P. Delammoge, J.C. Krupa, K. Rajnak, li. Genet and N.Edelstein, Phys. Rev. B 28 4723 <19B3).9B3).
2. R. Mchougliln, J. Chem. Phys. 30, 2099 (1967).
3. I. Richman, P. Krisliuk and E.Y. Wang, Phys. Rev. 1SS, 262(1961).
4. E.R. Vance and D.J. Mackey, Phys. Rev. B IB, 185 (197B).
- H -
2.3.1
ON THE DETERMINATION OF V»RATIOM TRANSITION DIPOLE MOMENT FROM
ROVBRATtONAL INTENSITIES : APPLICATION TO C L O AND HCL AS TEST
CASES.
Oman a N., T.K. Balasubramanian, N.D. Patel and V.P. B"llary
In an article published in a previous report , we discussed
the possibility of determining the vibrational transition dipole
moment from measurements of relative intensities of suitable
pairs of P,R branch lines in the rotation-vibration spectrum. In
situations' where the electrical anharmonicity is not particularly
significant it is passible to treat the rotation-vibration
intensity problem in the harmonic approximation. It also turns
out that in this case the goal of retrieving the transition
dipole moment may be readily reached through a graphical
procedure. The aim of this article is to illustrate the method
by taking two test cases - that of CIO and HC1. The choice of
CIO was made because accurate absorption intensities of the lines
in its fundamental band, measured using an FTS instrument was
readily available in the literature . Lines belonging to the
X na^2, v = 1 * X n 3 / 2 v = 0 transition, were used in our present.
graphical analysis. The graphical procedure, yielded <v=l \pt\ v
= 0> = - z.h X 10 D for the transition dipole moment which
compares favourably with - 3.64 X 10 D given in Ref.2 based on
a standard least squares analysis of the intensity data.
Encouraged by this success we next recorded the absorption
spectrum of the fundamental band of HC1 in the region 26019 — 3100
cm"* at a resolution of lcm1 using the Perkin-Elmer Infrared
Bpectrophotometer. The HC1 gas was produced by treating pur a
NaCl with cone. H2SO^ and Mas filled at a pressura of 170 torr
in a 10 cm long sample cell fitted with BaF2 end windows. Peak
abeorbances of the lines were taken as representative of the line
intensities in the subsequent analysis.
In the harmonic approximation, a plot of (l-VaTE) /<l+Va7E>
verses (J + 1/2) Cwhere a=ICR(.l) 3/ICP(J) 1 and b=U>[R(J> 3/ vCP<J>3>
X CSR(J'J)/SP(J'J)>3 should give a straight line graph passing
through the origin. Fig.1 shows such plots for CIO and HC1. Tha
slope of the line gives 4(/JO//J1O) (B«A>>S) where fjo and plo *rm,
respectively, the permanent and transition dipole moments, and B»
and co, are the usual molecular constants. Substitution of
appropriate values for HC1 yielded <v = 1 JM|V = 0> = + 0.03 D by
this method which does not compare so well with the true value of
0.072 0 reported in the literature. This drives home the point
that if this method has to succeed at all, the absorbanca
measurements have to be accurate to a fraction of a percent. To
achieve this kind of (relative) accuracies one may have to taka
full advantage of the ability of the FTIR instrument to "co-add"
repeated scans of the spectrum.
We are therefore planning to record the fundamental bands of
some typical molecules like HC1, CO, NO, etc. using the Bomem FT
spectrometer which has been in operation in our laboratory.
References :
1. Omana N., N.D. Patel, T.K. Balasubramanian and V.P. Bellary,in Spectroscopy Division Progress Report BARC-1536, (1990).
2. J.B. Burkholder, P.D. Hammer, C.J. Howard, A.6. Maki, 6.Thomson and C. Chacherian, Jr. J. Mol. Spectrosc. 124. 139(19B7).
-1.0«
-2.0
^ -3.0
> -4.0
i -5.o^ -fl.O
> - 7 . 0 -
1 "°-° '^ -10.0 L
x 10"fi
X = J + 1/2 *^
4 8 12 16 20 24 28 32 30I I 1 1 I
(A)
3/2 5/2 7/2 9/2 H/2 13/2 15/2 17/2X = J + 1/2 *
Pig.l. Graphical procedure for me determination of vibrational transitiondipole moment from the K/P line intensity ratios, in the fund«-mentfll band. (A) Data for CIO and (B) Data for HC1.
- Z l -
2.3.2
ROTATION-VIBRATION SPECTRUM OF OXYGEN MOLECULE : EST«-IATION OF
MAGNETIC DIPOLE CONTRIBUTION TO INTENSITY.
T.K. Balasubramanian, R.D'Cunha, V.P. Bellary and K. Narahari ft*o
The oxygen molecule is known to display an extremely weak
rotation—vibration spectrum which is mainly attributable to an
electric quadrupole transition. In our recent work relating to
line intensities in the quadrupole fundamental band of 02, MB
emphasized the need for incorporating intermediate coupling
[between Hund's cases (a) and ib) 3 in the X £g state, especially
for low J transitions. Due to the spin structure in the X £^
state, as many as 23 rotational branches can arise in this case
for which we gave closed form line—strength expressions holding
for intermediate coupling •
Associated with the electron spin angular momomentum of S=l
in the ground state of 02, there is a magnetic moment of 2pa
<uB=eh/4rimc being the electron Bohr magneton) due to which 0, is
known to exhibit a rather strong pure rotational magnetic dipole
spectrum in the microwave and far IR regions. By the same tokan
one might expect to see rovibrational transitions of magnetic
dipole origin in the fundamental band region which, if they occur
at all, should exist concurrently with the quadrupolar spectrum,
except for the difference that branches obeying AJ=±2 are
forbidden for magnetic dipole trnsitions. However, as has been
discussed elsewhere , the circumstance that the magnetic dipol*
* Oept. Phys., Ohio State University, Columbus, USA.
moment has no dependence on the internuclear separation,
precludes the occurrence of rovibrational magnetic dipole
transitions in the basic *pprax- nation and that any small
intensity that may result has to arise from indirect mechanisms.
Nevertheless, because of the vastly higher intrinsic strength of
magnetic dipale transitions in comparison with electric
quadrupole transitions, it is essential to consider carefully all
the mechanisms which cs>n impart non-zero intensities to magnetic
dipole rotation—vibration spectra. In this context we have
examined the following three mechanisms : (i) rotation—vibration
interaction within the 9E state (n) dependence of the
spin—splitting parameter X. on tha internuclear distance r and
<iii) spin-orbit mixing of the X 2g state with other electronic
states like 3n 9 or 4ng. A detailed consideration4 of rotation
vibration interaction in the X Z g state shows that there arise
two dominant terms in each transition amplitude which, due to an
accident of sorts, cancel each other more or less exactly, which
therefore results in negligible intensities. CWe have indeed
shown that this re&ult is true for all ZSHtE states with S>»/*3.
Separate estimation of intensity contributions due to mechanisms
(ii) and (iii) are found to be only around 1% and 3X of the
electric quadrupole contribution .
These conclusions, although they are in substantial
agreement with the inferences drawn in Ref.(1) regarding possible
upper limits for the strengths of magnetic dipole rotation
vibration lines, seem to be at variance with the recent
identification of s. few magnetic dipole lines in the Oj
-24-
fundamental band, derived from an analysis of tha ATMOS data9.
Further work is thus clearly warranted.
References t
1. J. Reid, R.L. Sinclair, A.M. Robinson and A.R.W. Mckeller,Phys. Rev. A24. 1944 (1981).
2. T.K. BalasubramanianT R. D'Cunha and K. Narahari Rao, J.Mol. Spectrosc. JL44f 374 (1990).
3. V.P. Bellary, Ph.D. Dissertation, University of Bombay(1989).
4. T.K. Balasubramanian, R. D'Cunha, V.P. Bellary and K.Narahari Rao, 45 Symposium on Molecular Spectroscopy, OhioState University Columbus, Ohio (USA) i RC2U990).
5. M. Dang-Nhu, R. Zander, A. Goldman and C.P. Rinsland, J.Mol. Spectrosc. 144., 366 (1990).
ZS-
2.3.3
ASPECTS OF FORBIDDEN TKANSIHONS SN DIATOMIC SPECTRA: UNE
INTENSITIES IN INTRA-MULTIPJXT TRANSITIONS.
T.K. BaJasubramanian, Oman a N and V.P. Bellmry
The advent cf large throughput spectrometers like the
Fourier Transf Droi Spectrometer (FTS) , in recent years, has opened
up the possibility of investigating extremely weak emissions
associated with an a.iazing variety of forbidden transitions in
diatomic spectra . Many or these weak emissions occur in the
near or mid infrared region inaccessible to photographic
recording and their FTIR detection, apart from the high
resolution capabilities, -fully exploits the two inherent
advantages - the multiplex and the large throughput advantages,
afforded by Fi ier Transform Spectrometry. Oftentimes this
method also seems to provide, rather routinely, realistic line
intensities o-f sufficient quantitative significance based on
which the mechanisms o-f occurrence of the forbidden transitions
may be modelled quite successfully .
The recent observation by Fink et als of the transition
X22ni/2 - X1
2nax2 of TeH ana TeD has prompted us to examine
afresh the intensity problem in this kind of transition. It May
be recalled that such intra-multiplet transitions, i.e.
transitions among different O uubstates 2S-*1. of a multiplet
electronic state (SSi/2) conforming to Hund's case (a), arm
forbidden for the electric dipole mechanism iiy the selection rule
A£ = 8 (on the spin projection?. Their occurrence as electric
dipole transition as in the case nf the Xs
transition of T B H or of the flKx'l^) - XO*(Xt£^>_o) of BiH <Fink
•t al9'7) in contravention of i.he above spin selection rule may
be traced to two mechanisms:
(i) rotation-induced spin uncoupling which progressively mixes
the various O substates and <ii> spin-orbit interaction which
imparts Hund's case <c) tendencies to the multiplet co«pon«nt« of
the electronic state under consideration. In the lighter class
of molecules which do not involve any high Z atoms, mechanism <i>
may be expected to be operative, whereas in the heavier class of
diatomics (ii) would be the dominant mechanism. Since diatomic
hydrides of even heavy elements have rather large rotational
constants (B-values) these molecules may exhibit appreciable
orbit—rotation or spin-uncoupling effects concurrently with the
spin-orbit mechanism which might noticeably distort the intensity
distribution in the rotational structure of such forbidden
transitions.
Intra-multiplet transitions, forbidden as they are by the
electric dipole selection rule, arc perfectly allowed by the
magnetic dipole selection rules. In practical situations, it may
be problematic to ascertain the electric dipole or magnetic
dipole nature of an observed intra-multiplet transition .
Knowledge of the absolute intensities cannot settle the issue
since what one would be comparing is the intensity of a perfectly
allowed but intrinsically weak magnetic dipole transition with
that of an ordinarily forbidden electric dipole transition mad*
allowed through indirect mechanisms. Our preliminary analysis of
the line intensities in the X^/s - Xta/> (0-0) band indeed
reveals a measurable orbit-rotation <0-R) contribution to the
-Z1-
line intensities and, vihot is more, th*» sign ac wall a* th»
magnitude o : this O-R contribution, somewhat -fortuitously in this
case, seem ':o rule out the magnetic dipole mechanism as tha causa
o-f this transition. Thi'.j feature hss prompted us to examina tha
line intensities in this particular transition more closely and
the details will be di tscusse'd in subsequent articles.
References i
1. C. Amiot. and J. VAfrges;, Clan. J. Phy. §?, 1391 (1981).
2. E.H. Fink, H. Kruias, D.A- Ramsay and M. Varvloot, Can. J.Phy. 64, 242 (1986).
3. E.H. Fink, H. Kruae and D.A. Ramsay, J. dol. Spactrosc. 119.377 (1986).
4. E.H. Fink, K.D. Seltzer-, U. Kottsieper, D A . Ramsay and II.Vervlcet, J. Mol. Spertrosc. 131. 133 (1981).
5. E.H. Fink, K.D. Seitzer, D.A. Ramsay and II. Vervloat, J.Mol. Epectrosc. 13JJ, 19 (1989).
6. V.P. Eiellary and T.K. Balasubramanian, J. Mol. Spactrosc.126, 436 (1987).
7. E.H. fink, K.D. Seitzer, O.A. Ramsay, M. Vervloat and J.M.Brown., J. Mol. Spectrost. 142. 108 (1998).
-26-
2.3.4
THE VBRATIONAL AND ROTATIONAL ANALYSES OF THE A*n-xV BANDS OF
8. Lakshminarayana and B.J. Shetty
Barrow (1) and Vago and Barrow (2) identified two electronic
bandsystems o-f silicon monoselenide (SiSe): A PI-X Z*
(2910-3670A) and E*Z*-X*Z* (2450-2770A). In 1965, Hoeft <3>
studied in the microwave region several rotational transitions in
v = 0-3 levels of the ground state of several isotopic varieties
<MSi7PSe, MSi*°Se etc.). In 1975, Lebreton et al C4>
identified a group of emission bands (3900-4300A) attributed to
the bant - X*Z* subsystem of SiSe. In 1977, Bosser et al (S)
performed the rotational analyses of the A-X and b—X bands.
Recently, Lakshminarayana . and Shetty (6) found a group of
emission bands in the 4000—6500A region and showed that these
bands togeather with the ultraviolet bands (2450-2770A) belonged
to the t Z*-X Z* system of SiSe. Here we report the results of
the rotational analysis of the A-X bands of Si*°Se.
The microwave technique used for producing tte emission
spectrum of SiSe was previously described <5). The A-< bands of
Si Se were recorded in the third order of a 10.6m Eb*rt grating
spectrograph at a dispersion of approximately 0.2A/mro. They
required exposures ranging from 3 to 10 hours on Kodak SA1
emulsion. The rotational lines were measured against thorium
lines (7) on- an automatic comparator with an estimated accuracy
of ±0.05 cm" for sharp lines.
The rotational analysis have been carried out by the
standard procedures (8). In most of the bands the analysis arm
straight-fc.rward and presefri(:'?d no difficulties.. The correct J
numberinij has been obtained by ins- ring agreement with the ground
state combination differences fi^F"(J)3 calculated from the
microwave data. It is further con-firmed by seeking agreement
between this upper state com'ji nation differences obtained from the
analyses o' several band's involving a particular vibrational
level. I'oi" this reason, the- bcinds have been so chosen for the
rotational analyses that cli&y invnlve common vibrational levels
either in iihe upper or' in th« lower electronic state. The
rotational analysis or 22 bands of Si Se have been carried out.
The rotational lines of dill bands involving a common upper
state (£ n> vibrational 1ft H) tiave been fitted by a simultaneous
least-squares program wnicli has yielded the band origins and
rotational constants. In the case of Si Se, Hoeft (3)
observed nine microwave transitions in the? v = 0-3 levels of X 51
and fche-.se lint»s are used l .i tl.i? simultaneous least square1"- fit
with a we ghtage of IB Ci .
Thi? rotational dnjlyi:.."; have yit?!ded the rotational
constants in the v = 0-10 v i tn- ati anal levels of the XI state.
These constants are found to be in satisfactory agreement with
the values calculated f r am t hi-? microwave data of Si Se. The
Bv values of the A*P stais (lahle I) have been fitted to the
formula:
B v = Btt - « a
The BB, aa and yo values obtained from tnis fit Are also included
in Table I. The present values of Pw and cx# differ slightly from
the vail ties of Bosser et ai (5). Furthermore, we have found
that, Ym is also required to represent satisfactorily the present
set of Bw values. The A-doubl nig has been found to be negligibly
small in all tha fiva observed vibrational levels of A n evtn at
the highest observed J values.
Table la Rotational constants (cm ) in the A n state of Si Se
0
1
2
3
4
0 .
0 .
0 .
0 .
0 .
167618(1)
166476(1)
165297(1)
164024(2)
162711(4)
1.
1 .
1 .
1 .
1 .
228(5)
200(4)
189(5)
151(1)
057(3)
CONSTANTS OBTAINED:
Ba = 0.16815(1) ac = 0.00107(1)
v = -0.000031(2)
Note: Values in parantheses indicate theuncertainties in the last digit quoted.
Finally the band origin data of all the 22 bands determined
from the present studies have been fitted in a least squares
procedure to obtain the system origin and the vibrational
constants for the A*n and X*£* states, which are presented in
Table IT together with the constants obtained by Bosser et al
(5). AH one can see from the table, the present set of constants
are better determined.
Bosser et al (5) did not report any perturbations. Me have
however, observed numerous rotational perturbations in the v •»
0—4 levels of A FI. The perturbations consisted ir» the shifting
of the rotational lines from their expected positions, although a
few instances of mere weakening of line intensity have also been
observed. The perturbations observed in a particular vibrational
level have been confirmed by observing them in several bands
involving that particular level. It should perhaps be remarked
here that WE have recorded under high resolution a number of
bands with v S 5 levels of API, but these bands have been found
to be severely r^rturbed and our attempts to analyse these bands
did not meet with success. To identify and to characterise the
perturbing states the rotational analysis of A~X bands of Si Se
is in progress.
-32-
Table H i Band origins in the A*n-X*£* system of 6i*°S«.
-*,System origin and vibrational constants (cm )
of A*n and X*£* are also included.
Band
0-0
0-3
0-4
B-5
0-6
1-0
1-1
1-5
1-7
1-B
2-0
T.«•'
<V x.'«•"
Band Origin
32359.12
30642.10
30076.51
29514.14
28955.33
32754.49
32178.79
29909.67
28795.17
28242.86
33146.29
Band
2-1
2-4
2-B
2-9
3-0
3-2
3-5
3-9
3-10
4-0
4-2
CONSTANTS OBTAINED
PRESENT
32449.27(6)
39B.77(4)
1.730(9)
579.03(1)
1.675(1)
BOSSER ET
32449.5 ±
398.9.,
1.7.
579.1«
1.6P
Standard Deviation: 0.06
Band Origin
32570.60
30863.56
28634.63
28085.80
33534.69
32386.66
30689.83
28474.19
27928.60
33919.70
32771.62
AL. (5)
0.5
Note: Values in parantheses indicate the uncertaintii
in the last digit quoted.
- 3 3-
References:
1. R.F. Barrow, Proc. Phys. Sac. 5_L, 267-273 (1939)
2. E.E. Vago and R.F- Barrow, Proc. Phys. Soc. 5_B, 538-54*(1946)
3. J. Hoeft, Z. Natur-forsch. £20, 1122-1124 <1965)
4. J. Lebretran, 6. Basser, J. Ferran and L. Marsigny,J.Phys. BJ3, H41-142 (1975)
5. G. Bosser, 3. Letiretr on anc! L. Marsigny, J. Chirn. Phys. 74.13-16 (1977)
6. G. L ' shdunarayana and D.J. Shetty, J. Mol. Spectro«r. 130.155-167 (19B8)
7. R. Zalubas, "New Description of Thorium Spectra," Natl.Bur. T>tand. Monograph 17, U.S. Department of Commwca,Washington, DC, I960
B. G. Her2berg, "Molecular Spectra and Molecular Structure I.Spectra of Diatomic Molecules," Van Nostrand-Rainhold, N«MYork, 1950
9. D.L. Albritton, A.L. Schmeltekopf and R.N. Zara, "MolecularSpectroscopy : Modern Research V/ol. II, K. Narahari Rao«Chapt. I. Academic Ptiss, New York, 1976.
2.3.5
THE ELECTRONIC SPECTRUM OF SILICON MONOTELLUROE CSITE)
Sheila Gopal, G. Lakshminarayana and H. Singh
The electronic spectrum of SiTe has been produced using the
enriched isotope of tellurium viz. 136) Te (99.67. enrichment) and
silicon metal. A new method ci-F excitation which is suitable for
producing the electronic spectrum of any particular isotopomer
(Si*28Te or Si19OTe) has been developed by adopting the microwave
(electrodeless) discharge technique. The spectra are recorded in
the first order of a 3.4m Ebert grating spectrograph at a
reciprocal dispersion of SA/mm and also in the 3rd order nf a
1(3.6m Ebert Grating Spectrograph at a reciprocal dispersion of
about 0.2A/mn, The results are discussed below.
E*r* - X V system (2800 A - 3180 A)
The E-X system of Si Te has been obtained in emission for
the first time. In the present studies several new bands
belonging to this system have been identified and their
vibrational assignments made. All the band heads have been
subjected to a least squares fitting which yielded improved sets
of vibrational constants for both the participating electronic
states viz. E and X. The present analysis has led to the
determination of the correct vibrational constant we = 229.66
cm for the E £ state which was erroneously determined as 240
cm" by previous workers (1). Table 1 gives the constants
derived from the analysis.
Table 1: Electronic and v:L^rational constants o-f E-X system of
State
Bi19OTe (in
34000.31
0
c:m 1
229.
4130.
£16
7 7
1
1
>* .
.190
.309
The dissociation energy oF Ei*aoTe molecule has been determined
to be 40,000 cm'1.
A*n - X*Z* system (32BCIA - 3900 A)
Tho rotational analysis of a number of bands belonging to
the A1!! - X*Z* system nt SI*9°Te molecule has been carried out.
The frequencies of the rotational lines of all the bands analysed
have aen fitted to the standard formula by least squares
procedure. The resulting band origins and the rotational
constants are presented in Table 2. No serious perturbations in
the v = 0 to 5 vilbrational levels were encountered. However,
as one goes to higher vibrational levels viz. in the levels v 6
severe intensity as well as positional perturbations have been
observer!. Analysis of these perturbations is und^r way.
-.it -
Table 2s Band origins and Rotational constants (cm ) for th«
Bandv'-v"
0-1
0-2
0-3
0-4
0-5
1-0
1-2
1-5
1-6
2-0
2-3
2-4
3-0
3-6
8-1
rt*n - X*E
Origin
28109.9
27635.0
27162.2
26691.6
26224.4
28293.7
27969.8
26560.6
26092.5
29255.1
27829.1
27359.1
29582.4
26754
30695.4
! system of Si
B*
0.124304
0.124Z80
0.124178
0.124365
0.124387
0.123537
0.123603
0.123664
0.123497
0.1225B5
0.122652
0.122475
0.121532
0.121691
0.117360
1 S OT.
D*x 107
0.55
0.68
0.61
0.77
0.70
0.78
0.79
0.78
0.64
0.72
0.71
0.56
0.67
0.68
0.52
B"
0.140856
0.140296
0.139634
0.139293
0.138791
0.141448
0.140454
0.138911
0.138190
0.141366
0.139844
0.139102
0.141523
0.138091
0.140767
D"xl07
0.36
0.48
0.40
0.57
0.5a
0.58
0.59
0.60
0.45
0.53
0.53
0.36
0.58
0.46
0.38
Referenc&B:
1. E.E. Vago and R.F. Barrow, 1946 Proc. Phys. Soc. 58, 538.
2. 8. Lakshminarayana and Sheila Gopal, 1990, Pramana - J. Phys.
Vol. 3J5, No.6, 519.
- 3 ? -
2.3.6
BROAD BAND EMKJSION SPECTRUM OF InBr AT 520 "*.
tt. Singh, G.S. Ghodgaonkar and M.D. Saksena
More experimental stud Las have been carried out an the green
emission bands of InBr at 520 nin. Indium is heated in a narrow
side quartz tube and a mixture of argon and bromine is allowed to
pass over the heated Indium at about 119 torr pressure. This
mixture is exciter] by a microwave discharge (2450 MHz) using 150
watts power. The emission gives intense green spectrum which was
recorded on a large quartz spectrograph. Thorium excited in mn
electrodt'less discharge tube and the Fe-trc are used as th»
standards. The accuracy of the line-like heads in the spectrum
is about ± 0.5 A. For reproduction purpose we have to record
this spectrum photoelectrically on a monochromator and then send
the revised manuscript to JQSRT.
2.3.7
ABSORPTION SPECTRUM OF I"B«"
H. Singh and R~V. Subr»mani*n
Pure InBr is synthesized by heating suitable quantity of In
natal and bromine in a quartz cell having 20 torr of neon gas.
The temperature is kept at about S00°C for 3 to 4 hours. Thw
synthesized InBr was having the required brownish-red colour.
The absorption spectrum of this compound is recorded on the
Hilger's medium quartz spectrograph at temperatures ranging from
200°C to 600°C. The expected fluctuation bands of the C*n - X*£
transition in the region 2800-3100A are obtained alangwith the
well known A-X and B-X systems of InBr in the near U.V. region.
The C-X spectrum is yet to be recorded photoelectrically on a
monachramatar, and to be compared with the simulated spectrum
using a computer program. Laser excited fluorescence and
opto-galvanic studies are also to be carried out on the C-X
transition.
2.3.8
SPECTRUM OF Hga
H. Singh &t><i R.V. Subraaanian
The experimental studies; were pursued on the electronic
emission .ind absorption speci.ra of Hg2 dimer which is a potential
candidate far a possible exciner laser medium. The interesting
•features :m the absorption spectrum are the four broad end
diffuse b.jnds at around 2345A. These bands appear to be Condon
Internal Diffraction pattern involving a stable upper state and
the repulsive ground state. This spectrum is to be simulated
using a computer programme for comparison with the observed
spectrum. Overlapping the above spectral features, a closely
packed band spectrum degraded to the? violet is also observed.
These two band systems are due to two different electronic
transitions.
For exciting the emission spectrum of Hg2, we have employed
several excitation sources such as (i) microwave discharge, (ii)
high voltage d.c. discharge and (iii) high voltage condensed
tranriorner discharge with a spark gap. These excitations gave
rise to Hg2 bands at around 2345A (a group of -Four broad and
diffuse bands identical to those observed in absorption) , 24BBJA
arJ 2540A. However, we could not succeed in getting all the
band systems reportrd by Takeyama (1952). Nevertheless, we have
carried out the vibratianal analysis of two band systems of
Takeyama (c, and g) at 4200A and 2718A, using his poor data we
are trying to develop a new source of excitation viz. Tesla Coil
Discharge which will enable us to get better data.
2.3.9
THE 430 NM SYSTEM OF INDIUM OXIDE
H.D. Saksena and H.J. Balfour
While the spectra of BO and A1O molecules have been
extensively studied the same cannot be said o-f the remaining
Gr.III A monoxides -for which little is known in detail. For the
Gad molecule only one band system viz. B I - X £ is known, for
which no satisfactory rotational analysis exists.
The spectrum of InO has been known for over fifty years.
Eventhough there have been several attempts (1-5) to investigate
the InO spectrum lying between the two In resonance lines at
410.2 and 451.1 nm, the BI* - XT* band system could not be
identified. All the previous workers had different opinions
about the transitions and classification of various InO bands in
the region.
Me have consequently photographed the spectr.i* of InO
produced by (i) an In-metal arc (35V, 3A), <ii) by a hollow
cathode and (iii) by microwave excitation (flowing mixture o-f
InClg vapours, argon and a small trace of oxygen). Th»
experimental techniques used in the present studies selectively
isolatead the B £ - X £ band system Df InO molecule and helped in
unambiguous vibrational assignments of the observed bands.
VIBRATIONdL ANALYSIS;
Two strong bands (23345 and 24001 cm 1) with associated
sequence structure and separated by 656 cm"1 have been observed.
Since the lower energy band group is considerably stronger He
Department of Chemistry, University of Victoria, Victoria B.C.,
VBW 3P6, Canada.
assigned ~he principal banc(«> as <0,0) arid (1,0). In each
sequence sands could bo followed with decreasing intensity upto
•five or six members. The blinds with v" = 2 <viz. 2 and 3,2
bands) appear enormously weak. This could be an indication of
interaction of closely lying A fl state with the X £ ground
state. The band heads are given in Table I.
The AG(v+—) intervals, nit the excited state vary smoothly
with v+- which gives approximate values of *># , u>m X, and um Ye
of 661, 7.5 and —lcm respectively. The lower state intervals
are suf-I iciently irregular so as to preclude an accurate
determination of the vibrational constants. We estimate w#" *
587 cm . It should be noted that the?a u>4 values differ
considerably from previous estimates.
ROTATIONAL ANALYSIS;
For the purpose of rotational analysis the spectra Her*
photographed on 3.4—m Ebert mounting spectrograph in the 13th
order of 5.7p blazed grating. The two stronger bands viz. 0f0
and 1,0 with v"=0 as the common vibrational level were selected
for the rotational analysis. In these bands the R—branch region
is crowded and not well—resolved. Super-f icial ly the P-branch
structure appears unusual with an illusion of "waves" of broad
structure, growing sharper with increasing N. The effect arises
from a combination of spin-doubling and varying degrees of
overlapping of the profiles broadened substantially and to
differing extents by hyper-fine coupling effect due to the ** In
nucleus. Two R-, two P-, and no Q—branches ars evident in the
spectrum. Therefore we assumed the transition to be a i — £.
The nuclear hyperfine splitting patterns appropriate to i states
have been discussed by Frosch and Foley (6) and by Dunn <7). The
01061: probable InO coupling scheme for a T state is that
designated as case bifiJ) by Dunn where, using the simplified
Hami 1 tonian H = b I.S, the overall widths of the hyperfine
multiplets are given by,
(for 2Zs>
AW(F4) = IC<N+l)/(2N+lM.b
= -ICN/(2N+l)3.b
(For " 5In0, I = 9/2)
The different signs for the Ft and F2 spin—components
signify that the hypermultiplet in one component is regular and
in the other inverted.
To proceed with the rotational analysis, the Pt and P,
branches are identified using the Mulliken's intensity criterion,
and the corresponding R{ and R2 branches, also located. For the
two bands viz. 0,0 and 1,0 the lower state combination
differences are matched. The analysis yielded two separata
origins for the Ft and F2 components signifying that even at N«O
the Ay is very large. Considering the spin—splitting constant in
the upper state to be positive, that of the lower state works out
to be negative with an initial large magnitude. It was possible
to determine unique rotational constants for the common v"HB in
both the oands for the F4 and F2 components. Later on the U n a
frequencies corresponding to the two components of the two bands
wera fitted in a simultaneous least squares fit. The resulting
rotational constants are presented in Table II.
The resolution used in the present studies is not enough to
resolve the extensive h.f. structure of different branches. We
have measured the most intense portion oi the hypermultiplet
branches- I-f the statistical weight (2F+1) o-f each component of
Ft and F 2 hyper oiul tiplets is taken into account it would result:
in a high frequency weaker component in Pt branch (or R4-branch)
and a lavs frequency component in P 2 (or R 2-branch). Because af
this the linij-frequencies used are not very accurate. Therefore
the constant's reported in T.able II should only be considered as
e-f-f ecti v€ .
Department o-f Chemistry, University o-f Victoria, Canada
REFERENCE:
1. Mar.jorie L. Guernsey, Phys. Rev. 46, 1".4-116 (1934).
2- W.W. Watson and A. Shambnn, Phys. Rev., 50, 607-609 (1936).
3. D. Jacquinot and H. Lavendy, Cr. Acad. Sc. Paris, 281B.397-399 (1975).
4. S.B. Osin, A.V. Yarkov and V.F. Shevelkov, Deposited Doc,VINITI, No. 234 <197B).
5. A.K. Rai, V.B. Singh, S.B. Rai and D.K. Rai, Ind. J. Phys.5BB, 246-251 (1984).
6. R.P. Frosch and H.M. Foley, Phys. Rev., 88, 1337-1349(1952).
7. T.M. Dunn, in "Molecular Spectroscopy: Modern Research", ed.by K.N. Rao and C.W. Mathews, Acad. Press, New York, 231-257
TABLE I
Deslandres Scheme for the *I* - X*I* band-system of InO
V
23346.423344.923342.923341.5657 t
24002.724001.223999.923998.0
588 23413.223412.0
64924061.924060.3
568 23493
63724130 573 23557.1
23555.8622
24179.524177.7
562 23616.923616.4610
24227.524225.8
560 23666.7
59224259.0
NOTE: The data (cm"1, vacuum) are from bandheads. ^secondary band heads
-45-
TABLE II
Rotational constants <in cm"1) of the B2£ and XZZ states of InO
State
B^CFi)
B2Z(F2]<
X2Z(F1)
X2E<F2>
V
0
1
0
l
0
0
Bv
i9. 2 9 7 4 2 ( 1 0 ) *
0.29519(11)
0.29568(12)
0.29397(12)
0.30703(10)
0.30413(12)
Dv K 10**
1.008(16)
0.952(17)
0.453(19)
0.579(21)
1.096(16)
0.465(19)
Band origins (in cm"*) of B2£ - X22 transition of InO
^oio^fV = 23 335.494(10); (F2) = 23 332.297(10)
l>i,o<F4) = 23 993.637(11); (F2) = 23 991.105(11)
Values given in parentheses are the standard deviations.
- 41 -2.3.10
THE SPECTRUM OF THE INO* MOLECULE
H.D. Saksena and tt.J. Balfour
In the? course of our study of the spectrum o-F InCl molecule,
the InO spectra were also excited. The InO bands (370-390 ran)
were first detected during experiments with a low-voltage (40V,
3A) dc arc, their single-headed appearance was in marked contrast
to the B £ -X £ bands of the neutral InO species occurring in
the neighbouring region. These bands were also developed in a
microwave discharge (2450 MHz, BOW) through a flowing mixti"~e of
InCl3 vapour, argon, and a trace of oxygen.
Table I lists the heads of the seven bands which have been
observed. Despite considerable effort no Av=±l sequence bands
have been found. The data have provided the first vibrational
fequencies for InO , namely To = 26772.7, to ' = 356.5,
o>9" XO'=3.7; to.,,' 503.5, w<,"X<>"=2. 1 (cm"1).
The identity of the spectral carrier is established through
the observations (i) that the 374.44 nm band shows a 2.78 cm"
shift on substitution of 0 by 0 <1>, and (ii> that the
rotational spectrum shows simple P, Q, R singlet—singlet
structure. The ground state of InO is expected to be £ and
the complete absence of nuclear hyperfine broadenings in the
bands, as seen in the (0,0) and (1,0) bands of B ^ - X ^ *
transition of InO (2) accords with this.
The (0,0) and (1,1) bands were photographed on a 3.4—m Ebert
spectrograph in the third order of a 30,000 l.p.i grating
(reciprocal disp. = 0.06 nm/mm). These bands have been
rotationaly analyzed in terms of a n- £ transition. The
-It-*-
A-doubling in the spectrum ie very small and becomes evident as a
combination defect only for J>70. The final constants ars listed
in table II.
Reference:
1. V.F. !3hevelkov, D.I. Kataev, and A.A. Maltsev, Vastn. Mosk.Univ. Ser. 2: Khim 24, 10Q-109 (1969).
2. W.J. Dalfour and li.D. Sakeena, to be published.
TABLE I
Band-heads in cm*1 and, In brackets, run
V
0
1
2
3
v" 0
26698.9(374.44)
1
499.8 26199.1(381.58)
349.5
26548.6(376.56)
2
494.6 25704.5(388.93)
348.4
495.9 26052.9(383.73)
342.0
26394.9(378.75)
3
26237.6(381.02)
TABLE XI
Rotational Constants (in en'1) for th* »II and X*X States of XnO*
»n x»i
B,
D
B
D
H
L
B
D
B
D
H
L
VI
r
,(RP)
,(RP)
,(Q)
»(R.P)
.(R.P)
x(Q)
iW
l
•
0.27090(9)
8.3(1) x 10'*
0.27091(9)
1.3(1) x 10-*
1.0(1) x,10-»»
-7.2(5) x 10-"
0.25790(18)
5.9(3) x 10-*
0.25791(18)
6.0(3) x 10-'
3.8(4) X 10-»»
-8.8(2) x 10'»»
26 691.00(3)
.2080 nm
0.28016(10)
4.61(8) X 10**
-
-
-
-
0.27127(17)
1.6(2) x 10'*
-
-
-
-
vio(l,l) - 26 5W.9K4)
Tm* - 0.2054 nm
2.3.11
THE SPECTRUM OF NCL*
M.D. Saksena and U.J. Balfour
Numerous spectroscopic studies of the InCl molecule have
been made, the most recent being those of Vempati and Jones (1),
Borkowska-Burnecka and Zyrnicki (2), and Perumals*my et al <3).
Three transitions have been identified in the ultraviolet. They
arm designated as ASno - X*£, B^-x'z, and C*n-X*5: and are seen
in absorption and emission. In addition a weak emission system
of 10 bands has been reported by Nampoori and Patel (4) between
390 and 410 nm, attributed to InCl, and assigned as A' £-X Z.
We carried out spectroscopic investigations in emission of
indium species, particularly InO, InCl and their positive ions
(5,6). It has been our experience that the so-called InCl A'X
bands invariably occur together with InCl bands. We surmise that
the Nampoori and Patel's A'-X bands can be readily accommodated
within the vibrational level scheme for the InCl*, B-X system.
Vibrational interavals, 95C1 /97C1 isotope shifts, and
Franck-Condon factors based on RKR potential curve support this
conclusion.
The spectra were excited using a Ni hollow cathode run with
2:1 mixture of In and InClg and 70—1(30 torr of helium carrier
gas. Spectra were recorded on a Jarrell-Ash 3.4-m Ebert
spectrograph at a reciprocal dispersion of 0.06 nm/mm. Also, the
microwave excitation experiments of Perumalsamy et al <3> were
repeated.
The B-X bands of InCl* and the so-called A'-X bands of InCl
lie in roughly the same spectral region and exhibit the same
-51-
general appearance. All are strongly red-degraded with no
discernible R-branch details apart -from an intense head. Th«
identi-ficatian of the B-X bands as being due to the ion had been
based on rotational analysis (6) while the attribution of the
A'-X bands to neutral InCl was circumstantial. It seemed natural
to speculate whether the A'-X bands could be accommodated within
the InCl* scheme.
To this end we computed RKR curves for the InCl* B and X
states. Franck-Condon factors were calculated from the curves
for a wide range of v-values in both the upper and the lower
states. It is clear from these calculations that Nampoori and
Patel's InCl A'-X bands and some unassigned observations of
Borkowska-Burnecka and Zyrnicki (2) and of Balfour and
Chandrasekhar (6) belong to the B-X system of InCl*. A
Desla,ndres tab^e, consisting of 45 In Cl bandheads, is
presented as Table I. Weak 97C1 isotope heads are seen for BOOM
of the stronger bands. This study provides the first vibratianal
data for the B state of InCl* and improved vibrational constants
for its ground state. The In Cl* bandheads fit the fallowing
vibrational formula:
v = 27,025 + 327.7 (v*+1) - 0. 631<v'+i)2
-0.0044<v*i)3 - C344.3(v"+i) - 2.849 <v"+i)2
2 2 2
- 0.117(v"+i)93
The quality of the fit, where calculated and observed
positions agree within experimental error, lends strong support
to the view that Nampoori and Patel's InCl A'-X bands be
reassigned to InCl* B-X system. Furthermore, excellent agreement
between observed and calculated chlorine isotope shifts is also
-si-
-found.
The proposed reassignment of Nampoori and Patel'• bands
conveniently removes the difficulty of explaining the unexpected
presence of a low lying excited *£ state in InCl when no such
analogous state is known for any related member of the group IIIA
halide family.
REFERENCES:
1. S.N. Vempati and M.E. Jones, J.M. Spectrosc. 152. 4SG-466(1988).
2. J. Borkowska-Burnecka and W. Zyrnicki, Physica C, 115.415-418 (1983).
3. K. Perumalsamy, S.B. Rai, K.N. Upadhya, and D.K. Rai,Physica C. , 132. 122-14B (1985).
4. V.P.N. Nampoori and M.M. Patel, Curr. Sci., 48., 532 (1979).
5. W.J. Balfour and M.D. Saksena, 3. Mol. Spectrosc., 143.392-395 (1990).
6. W.J. Balfour and K.S. Chandrasekhar, J. Mol. Spectrosc.,124. 443-449 (1987).
TABLE I Deslandres Table of Observed Band Heads (cmJ) assigned to the B-X System
v- 0
v1
0
1
2
3
4
5
6
7
8
9 29 907.4
10 30 220.1
11 30 531.2
12 30 843.9
13 31 151.7
10 11 12
26 349.0
26 675.0
26 998.8
27 644.2 27 3213
25 708.0
26 0343
26 359.4
26 683.6
25 401.0
25 728.0
26 0523
26 3772
27 021.4
25 103.7
25 429.8
26 0782
26 401.5
26 7213
24 816.2
25 467 JS
25 792.0
26 434.6
26 754.5
24 5403
24 866.9
25 191.9
25 838.5
24 275.0
24 6023
25 2512
24 022.7
24 350.4
24 675.0
25 6411
24 111.5
24 437.0
24 760.8 24 5342
24 857.5
The (v\l) progression is also present but these bandslie under stronger (v\0) bands and accurate beads aredifficult to estimate.
2.4.1
Low TEMPERATURE AND LONG PATH MULTIPLE REFLECTION SET UP FOR
DIODE LASER AND FTH? BMSTRUMENTS.
S.B. Kartha, V.A. Job and V.B. Kmrtha
Far many medium heavy molecules, the presence of low
frequency modes gives rise to relatively strong hot bands which
can distort the patterns of high resolution spectra even at room
temperature. Hence the need for a long path length low
temperature cell which can be used both with the FT as well as
diode laser spectrometer.
Me are fabricating a long pathlength C* S meters) cell
specially designed for use with the BOMEM FT instrument. The
optical beam of the instrument has 80 mm diameter. In order to
reduce this beam size, a Cassegrain type optical system has been
designed and tested. The reduced beam is then sent into a low
temperature cell (Fig.l). Our experience shows that a path
length of **5m will give good spectra (Ref.l).
In power reactor operations using heavy water as moderator,
the production of Tritium is hazardous. The Tritium has to be
removed by appropriate methods like laser isotope enrichment and,
other techniques. To develop methods for this as will as to
analyse for H9 spectroscopically, complete spectral information
on DTD and HTO is necessary. The normal concentration of If4 in
CIRUS heavy water is IB curies/litre. In terms of concentration,
this will come to 35 ppb. Power reactors will be operated
normally upto H9 build up of maximum saturation concentration of
35 curies per litre. Hence, spectra has to be obtained at thi
concentrations or lower concentrations only, since it is
hazardous to handle high concentrations of H .
For laser induced removal of Tritium, small changes of DTD
concentrations has to be monitored in the interacting system.
Studies on HDO by us (Ref.2) as well as by other authors (Ref.3)
show that natural concentration of HDO (300 ppm) give good
spectra at 4 torr and 50 m path length. Hence for H*
measurements, pathlengths of "'20-100 metre are required. Such a
cell is at present available with the diode laser system. Thi*
can be adapted for the FTS also using the Cassegrain optics. The
output beam of Fig.l will be about 10 mm diameter and this can be
matched with the multipass cell by appropriate optics.
At present, a C02 laser induced reaction of methylacetylene
with DTO is planned to be carried out. Table I shows some near
coincidences of C02 laser lines with CHSCCD CH3CCD has to bt used
in order not to dilute the reactor D2O. Since it is not possible
to handle large amounts of Tritium compounds, the multiple
reflection will be used to measure spectra of CH9CCT and other
tritium compounds. The multlipath length will also help to
monitor the formation or depletion of the isotopic Tritium
compounds which will be in the <ppm level concentration.
References:
1. P.K. Wahi, V.A. Job St V.B. KarthaJ. Mol. Spectrosc, 114, 305-320 (1985).
2. V.R. Rose Mary, K.B. Thakur, C.S. Samanathan, V.A. Job andV.B. KarthaProc. First National Symposium on Absorption Spectrometry180, 1984.
3. 6. Guelachvili3. Opt. Sac & AM, Vol. 73, 137, 1983.
-5L-
CD2 Laser
<Freq cm"1)
Table I
CH,CCD
<Freq cm1)
1090.0283
1082.2962
1078.5906
1074.6464
1071.8837
1057.3001
1046.8542
1037.4341
1033.4879
1029.4420
1023.1893
1018.9006
990.6196
989.6465
985.4883
983.2522
975.9304
970.5472
969.1395
963.2631
1090.0286
1082.2989
1078.5928
1074.6464
1071.8869
1057.298B
1046.8531
1046.4306
1043.4869
1029.4395
1023.1902
1018.8973
990.6209
989.6443
985.4890
983.2556
975.930B
970.5442
969.1384
963.2627
-59-2.4.2
FOURIER TRANSFORM HIGH RESOLUTION STUDY OF 2^,, BAND OF CDaCCH
Kuldip Singh, Geetha Rajappanr V.A. Job and V.B. Kartha
Propyne molecule has been investigated by many researchers
due to its presence on Titan, Orion and Taurus dark clouds.
Propyne has strong absorption in the 10 micron region and has
been effectively pumped by C02 laser to emit laser frequencies in
the MIR & FIR regions.
Low resolution spectra of CD3CCH in the 2v>p reagion was
reported by Spiers and Duncans who gave the J numbering of the P
and R branch and calculated B, D and 1t>o. We have recorded a
high resolution Fourier Transform spectra with a BOMEM DA 3.0192
spectrometer in the 2up region wilth an apodized resolution of
19.1304 cm (Unapodized Resolution 0.002 cm ). Globar source was
used with KBr beam splitter and MCT detector, sample pressure of
(9.5 torr was used in a one meter cell and 144 scans were coadded.
A cold spectrum of the sample was also recorded at dry ice
temperature (1185°K) and 62 scans were coadded. HDO lines
appearing at several places were used as standard lines to
calibrate the spectrum. Fig. 1 shows the resolved K structure in
the R-branch region.
More than 1000 lines of the P and R branch were assigned
upto J=50 & K=12 and fitted by least squares to a rms deviation
of 0.0004 cm" . No perturbations were included. Ground state
combination differences were used to determine the ground state
parameters and also to fix the line assignments. By comparing
the line intensities in the cold and room temperature spectrum
hot band transitions were identi-fied. Q branches of the tores
hot bands "2»9 + vlo - vtoi 2vp + 2vio - v±o and 3t>p - v9 were
assigned. This work was done in collaboration wilth National
Institute of Standards and Technology, USA.
References:
1. 6.K. Speirs and J.L. Duncan, J. Kol. Spectrose., Si,277-287 (1974).
R25
1 2 6 7 . 4 0 1 2 6 7 . 6 0 1 2 6 7 . 8 0 1268.00 1268.20
FIG. I. FT SPECTRUM OF CD,CCH
-u-2.4.3
PERTURBATIONS IN THE »>? STATE OF CD.CCH
R.3. Kshirsagar, CM. Medhekar, V.A. Job, V.B. Karthm
MethylAcetylene and its isotopic species are molecules of
considerable interest for several reasons. LHSCCH has been -found
in interstellar clouds and in the atmosphere of Titan. It is
also a possible candidate -for deuterium enrichment by laser
excitation methods. The 16^m laser oscillation has also been
observed in CHgCCH. The spectra of propyne (CH9CCH) and its
isotopic molecules provide very good examples of various kinds of
perturbations.
Absorption spectra of CD9CCK was recorded in the region
950-1150 cm""1 at an apodized resolution of 0.004 cm"1 at NIST.
The spectra was calibrated using HDD lines and calibrating
lines run on Fourier Transform spectra and diode laser spectra in
comparison with standard ammonia lines.
We have assigned about 2000 lines in this region belonging
to Pp, PQ, PR and RR, R^, Rr subbands.
Using these assignments we calculated the ground state
combination differences and least square fitted them to a
standard deviation of 0.0004 cm within experimental accuracy.
We also included few microwave values in the fit of combination
differences and have determined the ground state constants B, DJ,
DJK quite accurately.
The highly perturbed t>7 band shows some distinctive features
like the changing degradation in the various Q braevches. The
unperturbed RQQ and Pak from k=4 show degradation to high
frequencies while the other Q branches show degradation to lower
frequencies (see fig.l). This feature is mainly due to XV
Coriolis coupling of energy levels of u7 band with those of P 4
band which lie at 11161 cm" (see fig.2).
On the Po side as we go to higher k values, interaction
becomes weaker and only PQt and PQ2 show degradation to lower
frequency. On the R side as we go from RQp to higher k the
interaction become stronger until we reach RQP where the levels
cross over- This has led to changes in spectral pattern. The
Rn lines are observed to be widely spread.
The spectra also shows that at high J values the P M and Pmt
lines are split and the splitting increasing with J increasing.
This splitting arises from k-type doubling interaction between ut
and v7 and X—Y coriolis interaction. These splittings were
measured using diode laser spectrometer and the lines were
included in the fit.
Me also recorded the cold spectrum of RQO subband using
diode laser spectrometer to carry out correct J numbering of the
unperturbed RQO band.
In the least square fit of the data we included the
following essential interactions.
1. XY Coriolis interaction between v+ and v7 (AK = ±1, Lt = ±1)
2. K-type doubling between vA and f7 (AK * ±2, A/ = +1)
3. l-type doubling (±2, ±2) & l-type resonance (±1, 72) in v7
state.
The overall fit obtained was of the order of (9.002 c«~*
which is not as good as experimental accuracy.
Cold spectra of CD,CCH Mam recorded in the region 1080-1140
cm"1 using Bomem Fourier Transform Spectrometer, at an apodized
resolution of 0.004 cm*. The path length used Mas 1 «t. at *
sample prasssure of 10 Torr. The spectra was recorded at dry ice
temperature using liquid Nitrogen cooled MCT detector. With this
cold spectrum we are trying to identify the transitions to the vA
state which will give us a better determination of vA constants
and will probably improve the overall fit.
I .1 . 1 ... l.y»_- 1 ..I .1 «»..!.- . 1 -I I
1025.50 1032.50 1039.50 1046.00
- 6 5 -
1 1- /
10 / ,
1 / '• 1 " I 1
t1
8 / /
1 / '
6 / /f 1 /
5 / / .4 / / :"7 / ' ' /
L = - 1
////10 , „ . . - - - -
/ // '
q
/ / 8/ /
' • i "--6
* i b
' / / 5 ~ ~ - ^
/ / / O 7 1 vv w
/ ' ^ 0 ^CV"NN
t=0
11
10
8
7
6
54
32
11=1
V-7
'A3} Fl«-2
2.4.4
PERTURBATIONS M THE VIBRATION-ROTATIONAL HOT BANDS OF ACETYLENE
IN THE 2 6 5 0 - 4 - 1 0 0 CM"* REGION.
Y.A. Sarma and R. D'Cunha
The spectrum of acetylene in the 2650-4100 cm'1 region
consists of the CH stretching fundamentals and their combination*
wilth the bending vibrational modes along with their associated
hot bands. The interpretation of the high resolution spectra of
the bands m this region provides interesting examples of various
enharmonic interactions as well as vibrational—rotational I type
resonances.
We report here the analysis of some combination bands and
hot bands in the FTIR spectra recorded at Doppler limited
resolution. The bands investigated are
<v2 + v4 + vs> (A , E1) «— v<4 <ng> (2670 cm ~S
<vt + v4 + vs> (Ay, £*> «— v4 m9) (4075 cm"*)
A detailed study of the (vt + v4 + vs)
(Fig) hot band has shown that the assignment of the L^ and E^
sub—branches made by the earlier workers (1) based on low
resolution data needs to be interchanged. With this change in
assignment, it was possible to successfully locate the missing
*e' component of A sub-branch, leading to a satisfactory analysis
of the entire band system for the first time. The assignments
are also in complete agreement with the expected intensity
alternation in the various sub-branches.
In the analysis of the (v2+v^v9) (A^ZJ) 4- v4 <ng> band in
the 2670 cm"4 region, only the C component could be assigned
unambiguously. The other missing components are yet to b.
, i •
located and further work is in progress. Similarly, the <v2+3vg>
combination band located at ~4140 cm* (V.weak) is expected to be
perturbed by •f-type resonances between the <v2+3v»s) (nu) and
(V2+3L>S) i<pu) sublevels. However, only the transitions to the flu
sub lewis could be assigned and were fitted by the single bending
mode Harniltonian. The larger standard deviation of the fit and
the effective parameters obtained provide evidence of /-type
resonances. Transitions to the 4>u level from the ground state
are however forbidden and no suitable hot bands to this level
could be found and assigned in the available spectral region even
in the spectra recorded at higher pressures.
Referencess
1. A. Baldacci, S. Bhersetti and K. Narahari Rao, J. hoi.
Spectrosc. 48, 600 (1973).
- 4 8 -
2.4.5
HIGH RESOLUTION FTTR SPECTRA OF PROPYNE-D IN 9-11 VM REGION
S.B. Kartha, CM. Hedhekar, V.A. Job and V.S. Kartha
The 2v>p and uB bands of propyne-d lie in the region 90(9-1100
cm . The 2f0 mode of vibration gives rise to a parallel band
and the vB mode to a perpendicular band.
The absorption spectra was recorded in the 900-1100 c«i
region at NIST at an apodized resolution of 19.004 cm"1.
Assignements were made to P and R branches of 2u(> band for k «
0,1,2,3 upto J = 66, and to RR subband of v>a upto k = 9 J = 40.
Ground state constants were calculated by the combined least
squares fit of the combination differences of 7x>o parallel band,
um perpendicular band and microwave data. A standard deviation
of 0.0004 cm was obtained for the Fourier transform data and
microwave values fitted to an accuracy of 0.0000020 cm*.
Preliminary least square fit of the observed lines showed
that both 2Vf, and vn are perturbed. The 2v»p band contains son*
hot band transitions.
Cold spectra of CH9CCH was recorded in this region using the
Bomem Fourier Transfrom spectrometer at an apodized resolution of
0.004 cm . The path length used was 1 at. at a sample pressure
of less than 1 Torr. The spectra was recorded at Dry Ice
temperature using liquid Nitrogen cooled MCT detector.
The cold spectra shows a better resolution compared to the
room temperature spectra. also there is less crowding of lines
in the cold spectra due to suppression of hot band lines which
will make the assignment of the 2L>P bands easier.
SY0:CH3CC6789.BOX| D£T« MCT SOURCs GL1 B/$t KBR
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2.4.6
HIGH RESOLUTION INFRARED SPECTROSCOPIC MEASUREMENTS WITH THE
BOMEM DA3.002 FOURIER TRANSFORM SPECTROMETER
R.J. Kshirsagar, K. Singh, H.H. Deo, C. Hedhekar, G. Rajappan,
S.B. Kartha, R. D'Cunha and V.A. Job
The Bomem DA3.003 Fourier trans-Form spectrometer which was
installed in the division at the end of 1989, was used to obtain
high ri-'solution Fourier trans-form spectra of several molecular
systems of interest in isotope enrichment and laser development
programs. The spectra of various vibration-rotation bands of
NKjD, ND2H, CD9C = CH, CH3C s CD, PHa, PHaD, CH2F2, D20 and HDD
were recorded. High resolution scans were made with a 20 cm
pathlength cell placed within the sample compartment of the
instrument for the stranger bands while for the weaker bands the
beam was taken out from the side port of the instrument and
passed through a 1 meter cell and focussed onto the detector by
an off-axis ellipsoidal mirror. To eliminate complications dua
to hot bands arising from low-lying vibrational levels spectra
were also recorded at ""195 K by cooling the lm cell with dry ice.
The relevant details for the various systems studied arc
briefly described below:
NHjD, ND2H
The spectra of NH-jD and ND2H above 1100 cm'1 involve six
interacting levels. Out of these two are overtone levels, 2i£
and 2^2- These levels can be characterised only from the hot
bands vz —» 2P 2. We have recorded the spectrum of NHZD in the
»4*f ^ a , »4£ and L>«b regions (1200-156119 cm"1) at an apodizad
resolution of 0.005 cm I1 The spectra in tha region 600-1200
cm* have also been recorded to identify the hot band
-Tl-
transitions.
D20, HDD:
Fourier trans-form spectra of heavy water were obtained at a
resolution of ""0.005 cm* in the region 950-1330 cm'1 using a 20
cm cell and presure of ^10 Tarr. The cell was equipped with BaFa
windows to prevent attack by moisture. These measurements were
carried out as a prelude to extensive studies on the DTO molecule
which is important for recovery of tritium from the reactor
coolant and the analysis of the products of cold fusion.
Deuterated Methyl Acetylenes:
fe, 2fp and u7 bands of CD8CCH have been recorded at a
resolution of 0.004 cm . The v9 band was recorded with a liquid
He cooled SiB detector . The 2t»p and v7 bands of CD,CCH and 2vp
and fa bands of CH9CCD were recorded at room temperature as Hell
as at 195°K. The low temperatuare spectra have brought out the
salient features very clearly and have been of considerable help
in finalising the line assignments. A typical spectrum in the
region of the uo band is shown in Fig.l.
The High Resolution Infrared Spectroscopy of Phosphine (PH,)
has been found to be very helpful in understanding the various
physico-chemical processes in the atmospheres of Jupiter and
Saturn (1).
PHg has been studied quite extensively in the 9—10 fjm region
(2). For the 4—5 (urn region only low resolution information is
available (3). Me have recorded the high resolution FTIR
spectrum of PH, in the 2165-2465 cm'1 region where the two
fundamental bands of ut vB overlap quite strongly. The high
resolution FTIR spectrum of PH^D and PD2H is also being recorded
and studied. The PI-L.D and PD2H samples were prepared by
-1-2-pyrolysis of the required composition of deuterated H.PO,.
References:
1. P. Drossart, E. Lei 1 ouch, B. Bezard, J.P. Mai Hard andG. Tarrago., ICARUS 83, 248-253 (1990)
2. 6. Tarrago, M. Dang-Nhu and A. Goldman., J. Mol. Spectrosc.BB, 311-322 (1981)
3. A. Baldacci, V. Malathy Devi, K. Narahari Rao and G.Tarrago., J. Mol. Spectrosc., 81., 179-206 (19819).
- 7 - 3 -
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2.4.7
INFRARED ANb RAMAN SPECTROSCOPIC STUDIES or HGH-TC
SUPERCONDUCTORS & RELATED MATERIALS
S.H. Narang, H.D. Patel A V.B. Kirtha
For the superconducting compounds, it is normally a
difficult job to get good Infrared. Raman or visible spectra.
In our division, we are attempting to gain practical experience
and fabricate necessary accessories to obtain good spectra
covering wide spectral range from visible to far—infrared region.
Apart from the absorption mesurements, various techniques like
specular reflection, diffuse reflectance and Photoacoustic method
have been tried to obtain the best possible spectra. Spectra of
the thin films of Y-Ba-CuO (123) & Bi-Ca-Sr-Cu-0 (2122) were also
obtained.
For the low temperature studies, a low temperature cell
coaling down to liquid nitrogen temperature has been fabricated.
It consists of a liquid nitrogen dewar to which is welded a
capper sample holder whirh could be used for samples in the
reflection and transmission mode. The outer jacket of the dewar
is maintained at 10~ti torr. Deuterated Ammonium dichrornate was
used to test the temperature of the sample holder. As given in
the literature, we got a broad band in the range of 100(9—12130
cm at room temperature which splits into as many as 8 sharp
bands as the sample was cooled. This is according to the
expected splitting from symmetry consideration. Thus the
temperature of the sample seems to be reaching 90-100K.
-75"-
Using this low temperature cell, IR spectra were recorded
far Bi2Og and Y209 at various temperatures using a BOMEM DA3.002
FTIR spectrometer. Fig. 1 shows the IR spectrum -for Biz0, at room
temperature and at liquid 1^ temperature. As can be seen from
Fig.l, the room temperature spectrum shows a -few broad bands
which can be resolved by performing spectral deconvolution. Thus
all the -features which are not prominent at room temperature,
clearly r<tand out in the deconvoluted low temperature spectrum
(not shown here'.. Me are thus able to obtain 22 Raman
frequencies and 21 IR frequencies from low temperature spectrum
for BijgOg as shown in Table 1. For getting the remaining IR
frequencies, we have to cover the far—infrared region in order
to do a complete assignment. The Raman Spectra were recorded for
Bi209 & Y20g at various temperature using a Horney-MiI1er Cell.
Using these data, a complete spectral analysis is being done Cc
some of the assignments have been made.
The monoclinic c<—Bi Og with space group P2/C contains 4
molecules per unit cell, & the factor group analysis predicts 30
Raman active modes (IS Ag + 15 Bg) and 27 IR active modes (14 Au
+ 13 Bu) .
The cubic C—form of Y20a with space group Tn (lag) contains
8 molecules per Bravais unit cell. Twenty two Raman active modes
C4Ag + 4Eg + 14Eg3 & 16FU IR active modes are predicted, while 10
modes are both IR & Raman inactive. Raman 8c IR bands arm
expected to be mutually exclusive in both these compounds. The
assignments are being carried out for the observed spectra on the
basis of above mentioned symmetry.
The spectra of high-Tc Materials in the visible and UV
region arm of considerable interest. But normal absorption
techniques cannot be used in the these regions because of the
nature of the samples. To obtain spectra in these regions, a
Photoacoustic system was set up & tested for its performance.
Using excimer laser pumped dye laser, good spectra of test
samples of rare earth oxides could be obtained. The system will
now be used to obtain spectra for high-Te materials in visible
region.
Fig.2 gives an IR spectrum of Bi-Ca-Sr—Cu-0 (2122) as
recorded on FTIR instrument. Some work is being done to improve
the quality of the spectrum for the final use.
Table Is Vibrational Frequencies of Bi2O,
Raman
RoomTemp.
57
65
82
91
102
116
136
148
-
-
182
210
281
316
340
(cm *)
LowTemp.
57
65
82
91
101
118
138
146
151
156
184
210
281
314
340
In-frared
RoomTemp.
212
242
259
279
296
-
336
<cm"*)
LowTemp.
212
°243
a259
279
°296
a326
a349
Raman (cm" ',
RoomTemp.
412
-
450
>
LowTemp
412
430
448
In-frared (c
RoomTemp.
372(Sh)
388
464(Sh)
436
-
490(Sh)
512
593
-
-
-
671
690(Sh)
LowTemp.
372
393
a404(Sh)
436
a46B
°495
509
542
588
°619(Sh)
a637(6h)
a637(Sh)
°671
a690
r Not observed by earlier workers, Sh — Shoulder.
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- 9 o -2.4.8
DOUBLE RESONANCE STUDY OF NH« WITH TEA CO2 LASER AND DIODE LASER
Kuldip Singh, Rajiv S. Karve
An experiment was set up to study the double resonance
signals of NHg molecule using a TEA CO2 laser and a Diode Laser.
It involved pumping of NH, under collisionless conditions at ve.-y
low pressures by TEA COj laser and probing the rovibrational
populations with Diode Laser. Initial experiments aimed at
reducing the background RF noice and back scattering -from the TEA
C02 laser were carried out. CFaI gas at isotorr in 10 cm cell
was used to completely remove the back scattered TEA CO, laser
going into the diode laser. This work was done in collaboration
with Institute of Spectroscopy, Moscow.
MDRS, BARC, Bombay.
2.5.1
DETERMINATION OF ULTRATRACE LEVELS OF DEUTERIUM AND TRITIUM IN
H20
V.B. Karthaf H. Singh and R.V. Subrawanian
Experiments are being conducted to develop a spectroscopic
method -for the determination of Ultratrace levels of deuterium
and tritium in water. To start with, laser excited fluorescence
of OD radical produced in the microwave discharge through a -few
torr of D20 was tried. The 1,0 band of the AZZ* - Xznt system of
OD at around 2872A was excited by the second harmonic of th«
excimer pumped Rhodamine-6G dye laser. Attempts are being mad*
to record the fluorescence at 3065A due to (0,0) band of the A*Z*
- X 2^ transition of OD radical.
Prior to these experiments, electradeless discharge lamps
containing various pressures of H2O/DZO with and without rare gas
were prepared. When the discharge tube containing 2.5 torr H^O
was excited by microwave radiation, pure and intense spectrum of
OH was obtained without encountering impurity bands due to N^,
CN, CO, NO etc. The (0,0), (1,0) and (0,1) bands were recorded
on the medium quartz spectrngraph. One end of the discharge tube
containing D20 was partially cooled by liquid nitrogen in order
to reduce the pressure of D20 to a few torr at which a dischargs
was struck using microwave radiation for producing a clean OD
spectrum.
An electrical discharge tube with external electrodes and a
hollow cathode discharge tube ars being fabricated for trying an
alternate technique, viz. optogalvanic method, for
determination of the concentration of OD radical.
- 92 -
2.5.2
HIGH PRESSURE STUDIES OF COMPOUNDS USING LASER RAMAN SPECTROMETER
V.B. Kartha, A.P.G. Kutty*', S.N. Vaidya*, N.D. Patel and
S.VenkatesMaran
Introduction:
Phase transitions can be observed by Raman spectroscopic
methods. The phase transitions are usually brought about by
temperature changes, pressure changes, pH changes etc. The
existence of a high temperature phase in LiNaSO4 was reported by
Forland et al <1>. We have undertaken the Raman spectral studies
of LiNaS04 at various pressure to study the phase transitions
using diamond anvil cell.
Experimental:
The diamond cell used is an indegenous one made in Chemistry
Division. The diamonds are l/3rd carat each and are tested for
low fluorescence background. A thin stainless steel spacer "*25B(j
is inserted between the cones of the diamond. The spacer
contains a small hole in the centre ~200^ where the sample mixed
with ruby and ethanol methanol mixture is placed. Ruby chips aru
inserted to calculate the applied pressure.
Raman spectra are recorded using Spex Ramalog 1401
spectrometer coupled to a Wipro P.C. Spectral slit widths of 2-4
cm are used depending on signal intensity. We have used the
back—scattering geometry to record the Raman spectra. The
excitation line used was 5145A of an argon ion laser at 300 mW
power.
Discussion:
A detailed analysis of the IR and Raman spectra of LiNaS04
has been carried out by Dale Teeters et al (3). The internal
optic modes of LiNaSD4 is given by Tint » 9At + 9A, + 18E. The
^ & E modes are IR 8c Raman active. Raman spectra of the vx
region is shown in Fig.l. The vt region has threw modes of A*
symmetry. The modes are observed at 972, 998 fc 1026 cm"1. These
bands are the most intense bands and we have used these bands to
study phase transitions. When the sample is subjected to various
pressures in the range of 10 to 100 Kbar the spectral change
occur at specific pressure indicating phase transitions. Fig.2
shows the spectra at various pressures. Further experiments arm
being done to confirm the new phases.
Chemistry Division
References:
1. T. Forland and J. Krogh Moe., Acta Crystallogr., 11, 224(1958)
2. Dale Teeters & Roger French, J. Chem. Phys., 76, 799, 1982.
ND
VpRESSURE
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, )
Fig. I. Raman spectra of LiNaS0
110 kbar
9 2 kbar
5 6 kbar
4 kbar
• •
Fig.2. Raman spectra of LiNaS04
at different pressures.
2.5.3
PLASMA EMISSION CHARACTERISTICS OF LASER ABLATED SOUDS
A. Sharma and V.B. Kartha
Emission characteristics of plasma plume produced by
ablation of metals like copper and zirconium and high To ceramics
like Y-Ba-CU-D was investigated. In case of Y-Ba-Cu-O, many of
characteristic emission lines of Y, Ba and Cu as well as thair
ions were identified. In case of copper, a rich spectrum in
2500A-6B00A wavelength region consisting of emission lines from
Cul states both above and below the first ionization continuum
were identified. Plume emission spectrum was studied as a
function of distance from the target on which the lasir was
focussed with a spatial resolution of less than 1 mm. Figure A
and B show the plume emission spectra of copper for a distance of
1 mm and 5 mm respectively from the target. Clearly as ablated
atoms move away from the target they cool down rapidly and on*
sees a very simple spectral series from low lying states below
the ionization continuum whereas for points close to the targat
the emission spectrum is complex. Many autoionizing levels have
been identified.
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- 9 8 -
2.5.4
FORMATION OF ' THIN FB-MS BY LASER ABLATION OF HUH T«
SUPERCONDUCTINO MATERIALS.
A. Sharua and V.B. Kartha
A set up has been made to form supercnducting thin -films of
high Tc materials. A 300 mJ focussed XeCl excincr laser (308 rw)
is used to ablate a high Tc superconducting pellet like Y-Ba-Cu-0
which is rotating at 1 rpm to prevent formation of a crater on
the target. The substrate is placed 15-20 ma froai the target and
can be heatad conductively upto 750°C with a kanthal wire wound
heater. The evaporation has been done in 100-200 mTorr of oxygen
atmosphere. Upto now we have made oxide films on substrates like
quartz, sapphire, MgO and SrTiOa. These films were not
superconducting as the substrate temperature Mas limited to
400°C. Epi taxi ally grown films on MgO and Sr TiO, at &00-700°C
will be tried next.
- 6 1 -2.5.5
PULSED LAIJER INDUCED HOLE: BURNING IN AN AEROSOL MEDIUM: A NEW
TECHNIQUE FOR FLOW VISUALIZATION IN GASES.
A. Sharwa a\in1 S.S. Deshpande
Flow visualization techniques are routinely used in flrid
mechanics to observe and me.'c'usure properties o-f -flow -fields «»uch
as velocities and densities; . Many o-f these techniques arm
qualitative. The most common quantitative methods include laser
Ooppler anemometry which at any instant gives velocity at a
single point and laser speckle velocimetry ' which provides
instantaneous velocity -field over the entire plane o-f interest
but generally involves two step sequence of forming a specklegram
-followed by its processing to determine the velocity components.
Me discuss here a simple new technique to quantitatively
measure velocities in a flowing volume of gas. For this, we have
investigated the phenomenon of convection in a pyrex tube 30 cm
long and 2.5 cm in diameter [figure 11 which contains 150-700
Torr of air. The window A is of quartz to allow the 30B nn
excimer laser light CLambda Physik EMS 201 MSC3 to pass in wher«
as window B is of pyrex. Tho centre has a rectangular piece of
copper. -ocussed ex diner lar.i=r [pulse energy 80 mJ, duration 40
ns] falling an this piece of copper causes intense ablation of
the metal and the evaporation atoms condense in the surrounding
cold gas to form a dense smoke of capper aerosol particles which
is subsequently used for flow visualization. For this, th»
excimer laser is run at BHu -for 2 minutes. Focussed excimer
laser also heats up the piece of copper and a temperature rise of
about 10 C is recorded after 2 minutes of ablation. This
temperature difference between the hot piece of copper at the
centre and the relatively cooler ends of the tube sets up rapid
convection currents in the gas inside. As expected from the tube
geometry the convection currents move clockwise in the region BC
and anticlockwise in the region AC. This can be seen in figurt
2. To obtain this photograph, the copper aerosol is formed with
the pulsed c>;<c ner laser as described above. The excimer laser
beam is then cut off and the central part of the tube is
illuminated with a light-sheet9 from a CM argon ion laser (figure
1). Figure 2 is the traditional picture of flow visualization
that one obtains using Mie-scattering of light by aerosol
particles. While such pictures convey general qualitative idea
about the fluid flow there is no quantitative measure of velocity
field associated with it.
To obtain this additional information about flow velocities
the pulsed excimer laser beam is raised from its original path
(broken lines in figure 1) after the aerosol is formed to a
region just above the piece of copper (unbroken path in figure 1)
so that it does not ablate copper anymore. The aerosol once
produced, persists for many minutes, this time being governed
essentially by diffusion of aerosol particles and convection of
gas inside the tube . For air at 4013 Torr this time is around 20
minutes. The excimer laser light now passes clear through the
aerosol medium without any obstruction by the copper piece. Even
after substantial attenuation (40 mJ) a single pulse of focussed
excimer laser beam completely evaporates the aerosol particles
along its path, carving out what resembles a straight
- <\ I-
"aerosol-tunnel" in the Mitt-sc.atterino of argon-ion lastr
light-sheet incident from opposite direction. Because of gas
flow associated with convection this tunnel soon gets bent and
twisted in the plane of motion cH the gas (fig. 3a). However, as
compared to the convective maiss -flow the diffusion of aerosol
particles is very slow (measured < lmm/minute) . Thus even thought
the "aerosol—tunnel" gets bent in shape, the sharpness of its
edge is still maintained even a minute after it is formed.
Photographs 5a, b are taken in the Mie-scattered argon ion laser
light-sheet as the pulsed excinter laser is fired steadily at a
repetition rate of 1 Hz through the aerosol medium just above the
piece of copper. Soon after the aerosol is formed by the laser
ablation the copper piece is the hottest and maximum convection
velocities of around 5 cm/sec are observed close to the edge of
the copper piece. Before the second laser pulse can carve a
tunnel in the aerosol medium the first tunnel has been completely
swept away by convection. Thus at any instant one will see at
most one aerosol-tunnel in the Mie-scattered argon-ion laser
light (fig. 3a). The extent of deviation from the straight lin»
laser path is a measure of the convection flow velocity at that
point perpendicular to t.he 1 aser path. Photograph 3b is taken
after about 3 minutes h£iv«? elcipsed following laser ablation of
copper. The copper piece has. cooled down substantially and the
convection flow velocities are much reduced. Thus ona sees the
impression of many successive laser pulses (at lHz) each carving
out its own tunnel in the aerosol medium. The time interval to
travel from position of one to the next is precisely 1 second and
one can very easily map out the flow velocities in the plane of
the argon-ion laser light-sheet. Baa pressure for figure 3 is
600 Torr whereas in figure 4 same method is used with 1S0 Torr
pressure.
Referencesi
1. W. Lauterborn and A. Vogel( Ann. Rev. Fluid Meet). 16, 223(1984).
2. F. Durst, A. Mellig and J.H. Whitelaw, Principles andPractice of Laser—Doppler-Anemometry (Academic, London,1976).
3. L. Hesselink, Ann. Rev. Fluid Mech. 20, 421 (198B).
4. 6.H. Collicott and L. Hesselink, Opt. Lett. 13, 34B (1988).
3. W.J. Wang, ed., Flow Visualization III - Proc. Third Int.Symp. on Flow Visualization, Univ. of Michigan, 106, 1983(Springer-Verlag).
6. A. Sharma, Opt. Comm. 77t 303 (1990).
- 1 3 -
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- 9 4 -
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2.5.6
DETECTION OF SUB-PICOGRAM CONCENTRATIONS OF SODIUM BY ONE-STEP
LASER ENHANCED IONJSATION SPECTROMETRV
L.C. Chandola, P.P. Khanna and M.A.H. Razvi
The technique of laser enhanced ionisation (LED
spectrometry has. established itself as ultra-sensitive and
reliable method. In our attempt to lower down the detection
limit of sodium by LEI technique, we have investigated the
detection limits obtained by one-photon (3S-3P) line at 589.0 nm
and two-photon (3S-40) line at 578.7 nm. These transitions mrm
shown in the energy level diagram of sodium in Fig.l.
It has been found by workers in the field of ultra-trace
analysis that for sodium, there is a pick-up from reagents and
atmosphere below 1 ng/ml concentration. The detection limit for
sodium has, therefore, to be graphically calculated by
extrapolation of the working curve to noise level as given by
Bonchakov et al (Analytical Lett. 12(A9). 1037 <1979).
In our case, the noise level was fixed by recording the
deviations in the background spectrum of a standard sodium
solution on a strip—chart recorder. The spectrum was run on 50
mV range full scale (250 divisions) of the chart meaning that
each division represents 0.2 mV. In this range the Maximum
variation was found to be two divisions i.e. equivalent to 0.4
mV. Putting the noise level at 2.5 times the variation, i.e., at
1 mV, we have calculated the detection limits.
The calibration curves obtained by 5B9.0m nm and 578.7 nm
lines are shown in Fig.2. When extrapolated to the noise level,
the one—photon line at 589.0 nm gives a detection limit of 0.02
ng/ml and the two-photon 578.7 nm line gives a detection limit of
0.1 pg/oil.
The sub-picagram/f>u limit for sodium by one-step excitation
is being reported for he -first time. This has been mad*
possible by the use ui wo-photon 578.7 nm line for analysis
which gives better intensity than 589.0 nm line at low
concentrations.
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TWO PHOTON (3S-4D) AND ONE PHOTON ( 3 S - 3 P )TRANSITIONS IN SODIUM ENERGY LEVEL DIAGRAM
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t iii in
I!
! . , - ' • •
I i i i f i i i r f \ i f t t n i i i i i t i m i
578.7
. . • • • - ' ,*•*
••*•
1 f | ll|ll 1 1 1 1 Li
^ /
/
^ 5 8 9 . 0 nm
NOISE LEVEL
0 0001 0.001 0.01 0 1 1.0 10 100 1000
t CONCENTRATION ( n g / m l )(ZS-C) FIG.8. CALIBRATION CURVES FOR SODIUM BY LEI
— Joo -2.5.7
EFFECT OF LASER POWER ON LEI SIGNAL OF ONE-PHOTON AND TWO-PHOTON
LJNES OF SODIUM
L.C. Chandola, P.P. Khanna and M.A.H. Razvi
The effect of laser power on laser enhanced ionication
(LEI) signal was investigated both for one-photon 3S-3P
transition line at 5S9.B nm and two-photon 3S-4D transition line
at 578.7 nm. The dye laser beam was attenuated by introducing
clean glass plates perpendicular to the path of laser light
successively. Each plate gives an attenuation of about 4% at
each of the two surfaces. Mater containing SB, 100 and 200 ng/ml
of sodium was aspirated in the flame. The LEI signal was
recorded in the usual way (1). The results are shown in Fig.l
which shows that with attenuation of laser power the two-photon
line signal falls off more rapidly compared to one-photon line
signal.
Calibration curves for S89.0 nm and 578.7 nm lines are
plotted at different powers of the laser beam which are shown in
Fig.2. It has been established by us that the slope of the
two-photon line at 57S.7 nm is lower than that of one-photon line
at 589.0 nm. Therefore, with high laser power, at low
concentrations Df sodium, the signal for two-photon line is
higher than that of one-photon line. This results in better
detection limit for the two-photon line. This effect is also
responsible for the observation that these lines appear in LEI
spectrum with varying intensities with respect to each other
depending both upon the concentration of sodium and the power of
the laser beam.
- i o i -
The ratio of LEI signals Na 576.7 n«/Na 589.0 n» is
plotted at various concentrations of sodium and has been shown in
Fig,3. This -figure shows that the relative intensity of
two-photon line is smal er at hgiher concentrations of sodium.
Reference:
1. L.C. Chandola, P.P. Khanna and M.A.N. Razvi, ReportBARC-1510 (1990).
x 10J
7r
6b
5
I.
200 ng/ml
100 ng/ml
50 ng/ml
LASER-18 kV / 8 HzNa 578.7 nmNa 589.0 nm
ai
0 1 2 3 4
5 ? ) F , 3 i NO. OF GUSS PUTE ATTENUATORS — -LEI SIGNAL OF Na FOR TWO PHOTON 578.7 n m (3S-4D TRANSITION)k SINGLE PHOTON 589.0 n m ( 3 S - 3 P TRANSITION) WITH DIFFERENTLASER POWER ATTENUATIONS AT VARIOUS CONCENTRATIONS
Na 589.0 nm
Na 578.7 nmLASER POWER - 18 kV / 8 Hz
ATTENUATION BYNO GLASS P U T E
B3 150 100 200CONC, ng/ml
ATTENUATION BY V ATTENUATION BY , • > ATTENUATION BY1 GIAS5 PLATE 2 GLASS PLATES 3 GLASS PLATES
50 100 200CONC. ng/'ml
50 loo :.JOCONC., ng m"
ATTENUATION BY4 GLASS PLATE3
50 100 200CONC, ng/m:
7) F., ^EFFECT OF ATTENUATION OF LASER POWER OX WORKING TURVES FOR TWO PHOTON
57B.7 nm (3S-4D) AND SINGLE PHOTON 589.0 nm (3S-3P) LL\ES FOR Na
50 100 200CONC., ng/mi
(Z 5- ?)
8~2.0
®1.0o
i Na 578.7 n mNa 589.0 n m
Io-r
i
10 100 1000CONCENTRATION OF Na IN WATER (ng/ml)
RATIO OF LEI SIGNALS OF TWO PHOTON 578.7 n m (3S-4D TRANSITION)WITH SINGLE PHOTON 589.0 n m (3S-3P TRANSITION) OF Na AT VARIOUSCONCENTRATIONS.
2.5.B
EFFECT OF LOW AND HIGH IONISATION POTENTIAL ELEMENTS ON LASER
ENHANCED IONISATION SIGNAL OF SODIUM
L.C. Chandola, P.P. Khanna and M.A.H. Razvi
The ionisation potei ' ials (IPs) of -five alkali elements are
given in Table-1.
Table li Ionisation Potentials of Alkali Elements
Elements Ionisation Potential, eV
Lithium <Li) 5.37
Sodium (Na> 5.12
Potassium <K> 4.32
Rubidium <Rb) 4.16
Cesium (Cs) 3.87
Lithium has ionisation potential higher than that of
sodium but other three elements have ionisation potentials lower
to it. Therefore, this group of elements provide an excellent
choice of metals to see the effect of IPs on LEI signal of
sodium. A study was therefore made in which various amounts of
lithium, potassium and cesium were added to water containing
sodium and ionisation signal of one—photon 589.0 nm and
two—photon 578.7 nm lines was monitored. The results are given
in Fig.1.
It is seen from these results that intensities of both
one—photon and two—photon lines of sodium are affected by the low
ionisation potential elements potassium and cesium whereas there
is no change in the sodium signal by addition of lithium which
has a higher IP. In the case o-f cesium, initially there is a
small increase in the LEI signal which later falls off. This
shows that the presence of ions of cesium help the process of
excitation and ionisation to some degree when present in small
amounts.
12 rEFFECT OF K ON Na SIGNAL
1ONISATION POTNa 5 . . 2 eVK 4.32 eV
EFFECT OF Cs ON Na SIGNAL
I0MSATI0N POT5.12 eV
eV
Na 589.0 nm
Na 578.7 nin• ' « •
30 60 90CONCENTRATION fN ( i | / m l
12 r
j . BFFR
4BFFRCT OF U ON Na SIGNAL
JO 60 90 120Cs CONCENTRATION IS
Na 589.0 nm
IOj
NaU
m
.1SATION
5.12 eV5.37 eV
Na 5787
i i i
POTENTIAL
nm
i ' *0 30 60 90
U CONCENTRATION S
i EFFECT OF AMCAU ELEMENTS ON I.EI SIGNAL OF SODIUM
-- J o t. -
2.5.9
MOLECULAR PHOTOPHYSICS
J.V. Venkitachalam and A.S. Rao
The main activity of this group is to study the spectroscopy
of atoms and free- radicals generated by photodecomposition of
molecules. The basic photophysical process involves the
absorption of a quantum of light and the consequent formation of
the molecular system in an excited state. If the incident energy
absorbed is over and above the energy required to break the
weakest bond of the system, then the excess energy is manifested
as the internal energy of the fragments. In order to study such
phenomena an experimental system is built up and the block
diagram of which is shown in figure 1.
This is basically a pump and probe experiment. The pump
beam (XeCl: 308 nm> is used to dissociate the parent molecule and
the transient photof ragments are probed by an ex c inter pumped dye
laser tunable in the 2719-806) nm range. The probe beam is delayed
from pump beam optically from a few nanoseconds to micro seconds
by using a multipass cell. About 5-20V. of the excimer beam is
used for dissociation and the rest is used for pumping the dye
1aser.
The phatodiBBOCiation is carried out by one or multiphoton
absorption depending on the molecular system under study. The
photafragments are detected by laser induced fluorescence (either
by one or two photons) or (2+1) REMPI technique (either same or
different colour photons).
1. Single photon Laser Induced Fluorescence (LIF) z
The pump and probe beams cross «t right angles (or
alternately they can be made roughly parallel) and tuning the
probe beam over the frer .ency range one can obtain the excitation
spectrum of the radic i which would help in the characterisation
of the radical.
2. Two Photon Laser Induced Fluorescence :
In the case of atoms and molecules where resonance
transitions lie in the vUv", this can be reached by multiphoton
excitation using visible photons. Ely making use of proper dyes
-fundamental radiation of interest can be produced which on
frequency doubling by using approprate crystals produce UV
photons. Two such photons can excite the atoms under study to
high levels which decay via an intermediate state to ground stats
emitting a VUV photon. This VUV photon can be detected using a
solar blind photomultiplier.
3. Resonance Enhanced Multiphoton Ionisation (REflPI) »
In the case of systems which are excited resonantly by two
photon absorption, a third photon either from the same probe beam
or one from pump beam can ionise the sytem. This is detected by
making use of two parallel plate electrodes. This technique is
useful when either the parent or one of the products fluorescence
on excitation.
These type of experiments would help us to understand,
1) The spectroscopy of transients.
2) State to state detection of nascent photofragments.
3) Dynamics of photodissociation.
4) Development of new schemes for MPA etc.
r
l_
PRE AMPLIFIER
BOX CAR AVERAGER
EXPERIMENTAL CHAMBER\
BEAM DUMPPUMP MODULE -JjT
EXCIMER LASER
TP.M.TUBE STRIP CHART RECORDER
OPTICAL DELAY(MULTIPLE REFL. CELL)
SAMPLE INLET
BEAM SPLITTERoo
DYE LASER
P.-. i
i
o
- l l i -
2.5.10
Two PHOTON SPECTROSCOPV OF AUTOIOMSMG LEVELS OF SINGLET SULPHUR
C31SO>
T.V. Ve <itachalam and A.S. Rao
Introduction:
The lowest election configuration of SI is Is 2s 2p 3B 3p
which gives rise to P 2 1 O, D2 and So states lying in the
ascending order of O, 9239 and 221819 cm" respectively. By the
removal of a p electron the SI I ion is formed which has S , D
and P° as its lowest states corresponding to the energies at
82S59, 9B412 and 1198084 cm"1 respectively. Thus discrete states
are possible to exist above the first ionisation limit. These
levels can decay either by the non—radiative process of
autoionisation or return to lower states by radiative decay. In
this study we have observed that sulphur atoms excited from 3s
3p ( P ) core by two photons lie above the first ionisation
limit. The energy states have been characterised. It is
proposed that autoionisation is a dominant mechanism in the decay
of triplet states, where as it is more probable for the singlet
states to absorb a further photon and consequently undergo
ionisation.
Experimental:
An excimer laser (Lambda Physik EMG 2(91 MSC) pumped (308
nm) dye laser (FL 3022) using Rhodamine 6G produces the
fundamental in the region 570-610 nm. This is frequency doubled
using a temperature stabilised, angle tuned BBO crystal
(FL—37— 1). This radiation is focussed at the centre o-f reaction
cell through which purified CS2 gas was flowed at a pressure of
50 mT. Two parallel plate electrodes made of copper was kept at
a distance of 1", central to the focal spot. Typical d.c.
voltages of 10-100V were used in the experiments. The ion
current was preamplified and fed into a box-car integrator whose
output was displayed on a strip chart recorder.
Results:
It has been observed that C52 undergoes photodecomposition
by sequential absorption of two UV photons and the photoproduct S
atoms were detected in the excited 3p D2 and 3p So states
(1). The excited S fragmentas were probed by three photon (two
to resonance) ionisation technique, using same colour laser
photon. The photodissociation and photofragment detection is a
result of a five photon absorption process from the same laser
pulse. The scheme of events can be represented as:
CS2(X1Zg) hU > CS2* , CS,**
CB/* c-* CS(a9n>+ S<3P)
cs (x1^) + s<iD, is,
s* hu > s*
The sulphur atoms were probed at selected laser
wavelengths. Figure 1 shows the spectra of S* ions produced by
multiphoton excitation from lower 3s 3p* *SO level.
- in-Discussion:
Prior to this study not much information was available on
the higher excited levels of even parityt excited from the lower
3s23p* *SO level preserving the same ion core. This may be
because all the photoabsnrption and photaionisation experimants
performed so far used single photon techniques. As the ground
and lower states of S belong to even parity, these studies
provide a wealth of information on higher excited states of odd
parity through 3p-ns, 3p-nd allowed transitions (2-4i. When a 3p
electron is promoted to a 3s 3p ( P )4p orbital, the probable
energy states are S1, P and D with multiplicities singlets and
triplets, all of even parity. Assuming Russel-Saunders coupling,
the selection rules for two photon transitions are AS=0, AL=0,
±1, ±2 and AJ=0, ±1, ±2; A£=0, ±2 and parity conservation. The
observed lines are assigned on this basis along with the special
selection rule applicable in the case of two equal photons viz.
J=0 «—|—• j = l. All the transitions observed correspond to A/=0T
3p—4p. The results of these studies, such as the energies of the
intermediate levels reached by two photon absorption, excited
state configuration and probable state characterisation based on
R—S coupling are presented in Table 1.
It has been observed that all the even states excited by
two photons from the lower 3 So state be above ths first
ionisation potential viz. 5* < S9X2)at 83559 cm . The maximum
single photon energy used in these experiments is approximately
4.35 eV. Hence by two photon absorption only atoms in 3 So
levels can be excited to near or above the first ionisation
potential. These levels are the initial states of np Rydberg
series that converge on the ZP excited state of S*. These
states can decay through two routes, either non—radiatively via
- l i i f -
autoi oni sat ion into continuum generated by the coupling of
( S3/,2) ionic state with the Rydberg electron or they may
radiatively relax to lower states by spontaneous emission.
Treating the Rydberg states of the S atom in a first
approximation as con-Forming to L-S coupling, a number of
selection rules can be applied to autoionisation (5). The *S
ionic state can couple with a 3p electron producing po.i,2 a n a
P1>2,9 cantinua. For electrostatic autoi oni sat ion the following
selection rules are valid. AS=0; AL=0T AJ=0 as also parity
conservation. Thus two photon excited Pj Rydberg states can
autoionise into the 9Pj continuum generated as described above.
The singlet states cannot autoionise directly within the L-S
coupling frame work as no singlet continuum is produced. But the
spin-orbit interactions can lead to a break-down of L-S coupling
and allow autoionisation of singlet into triplet which in this
case is much smaller than the electrostatic autoionisation. The
permissible selection rules for such a process are AS=0, ±1,
AL=0, ±1, AJ=0, and parity conservation. When the spin—spin
interaction, which is still smaller than the spin-orbit'
interaction, is also taken into account the allowed selection
rules AS=0, ±1, ±2, AL=0, ±1, ±2, AJ»0 and parity conserved,
permit autoionisation. Thus both the spin-orbit and spin-spin
interactions though much weaker compared to electrostatic
autoipnisation, open up additional pathways for autoionisation of
singlet levels. However, a power dependance study shows that in
case of singlet states, a third photon absorption and subsequent
icnisation is more probable.
- its- —
Reference:
1. T.V. Venkitachalam and A.S. Rao - to be published.
2. C.E. Moore: Atomic Energy Levels, Circ. Natl. Bur. Stand
(USA) Vol.1 (1949).
3. G. Tondello: Astrcphys. J. 173. 771 (1972).
4. Y.N. Joshi, M. Mazzoni, A. Nencioni, W.H. Parkinson and A.
Cantu: J. Phys B. 20, 1203 (1987).
5. P. Feldman and P. Novick: Phys. Rev. 160, 143 (1967).
Table £: Assignments of observed multiphoton 3pectra of S atom
excited from 3s23p* *Sb level.
ExcitationWavelength Wavenumber\air (vac^nm cm
290.015
295.963
293.068
299.150
299.178
299.272
299.345
2S9.400
299.575
299.781
300.126
300.33
34470.9
33778.1
33427.5
33418.3
33415.2
33404.7
33396.5
33390.4
33370.8
33348.0
33309.6
33287.0
Twophotonenergy
66941.8
67556.3
66855.0
66836.6
66830.4
66009.4
66793.0
66780.8
66741.6
66696.0
66619.2
66574.0
Excited state
Config Desg
3s23p3(2P0)4p
3s23p3(2D0)5p
3s23p3(2P0^)4p
3s23p3(2D0)5p9 "\ 7 OS
3s':3p>5rp3.,2)4p
3s^3pVPtU)4po -3 n of
3s^3p<3('iP^)4p
3s23p3(2P0,2)4p
3s23p3(2P0/,2)4p
3s23p3(2P0^2)4p
3S^3PVP;U)4P
4p1S
s p ^
4p3P
5p3P
4p3P
4p3P
5p3P
4p3P
4pXD
4pXD
4p3D
4p3D
J
0
2
0
0
2
0
2
2
2
2
2
2
EnergyLevel0
2h^ + Eo
91121.8
89736.3
89035.0
89016.6
89010.4
88989.4
88973.0
88960.8
88921.6
88876.0
88799.2
88754.0'
aVacuum Wavenumbers taken from Table of Wavenumbers, Vol.1,
C.D.Coleman, W.R. Bozman, W.F. Meggers, Natl. Bur. Stand (1960).
Two-photon excited intermediate 3tate energy calculated by
adding to the two-photon energies, the energy (22180.0 cm ) of
3*So above ground *P2 level (ref.3).
1 1 7 -
ffffffffo r » n n n n r » " »I l l l l l i l
(is-10)
2.5. V
C2+1> REMPI SPECTROSCOPY OF EXCITED C3*D2) SULPHUR ATOM
T.V. Venkitachalam and A.S. Rao
Introduction:
Lasers because o-f its high photon -flux can be gainfully
employed to study the interaction of radiation with systems that
are not amenable to single photon interactions. By using
multiphoton absorption process, one can proba a transition
occuring at VUV region, using visible photons or one can probe
the "dark" states that are forbidden by dipole selection rules.
Resonance enhanced multiphoton ionisation (REMPI) is a sensitive
technique to study the transient species that are formed
consequent to photodissociation of the parent molecule. In this
paper we discuss the two photon transitions excited from 3s 3p
D2 level of the S atom. S atoms are generated in this excited
state by two photon photodissociation of CS2 in the gas phase in
the region 285-305 nm.
Experiment 8c Results:
The experimental set up has been described elsewhere (1).
In this study we probe the upper excited states of even parity by
two photon excitation of the S atom from the lower 3s 3p* D2
state. When a < D >3p electron is promoted to the 4p orbital,the
expected states are *'*PJf *'9D, and '"'F,. All the lines have
been assigned assuming R-S Coupling and applicable two-photon
selection rules described elsewhere (1). Transitions from lower
-in-3*D2 levels to all upper levels have been observed except to *Pj
state. This is mainly because these transitions occur at the
lower limit of the dye used. The energies of the intermediate
state reached are determined by adding to the two-photon
energies, the energy of 'X, viz 9239 c«i"* with respect to the
ground level 9P2. The reault of these studies are tabulated in
Table 1 and the spectra are shown in fiqures 1 and 2.
Mainly three types of transitions are observed, 1)
Singlet-Singlet 2) Singlet-triplet and 3)non~core preserving
transitions as shown in the figures. Singlet-Singlet transitions
are intense compared to singlet-triplet transitions. The
intermediate state reached by two photon absorption lie well
below the first ionisation potential viz <*S°) of 5* at 83559
cm . Hence the absorption of a third photon is essential to
ionise the atom.
The transitions observed at 291.146, 291.16, 291.196 and
291.413 nn arise from states that do not preserve the ( D > core.
These transitions involve the two—photon excited upper even
parity state configuration 3s 3p ( S ) 6p giving rise to states
' Pj. It can be seen from Table 1, that the energies of (*S°)6p
SP4, <*SO>6pBP4 and (2D°)4p1P1 are very close.
Hence, there is a -finite probability that these states can
perturb one another if certain selection rulesare satisfied. The
rigourous selection rules for pertubrations are AJ = 0 and parity
conservation. Because of this perturbation the lower level
can be coupled to the 6p Pt and 6p Pt states through the cor*
preserving excited level 4p P1. Jakobsson has observed similar
perturbation in the i.r. emission studies of S02 discharges (2).
Similar configuration interaction between the excited levels of
6p*P2, &p9P2 and 4p^ 1D2 may be responsible for the observation
of 3*Dfc > * 6psP2 and 3*D2 > » 6p*P2 transit ions at the two
photon excitation wavelengths 291.396 and 291.216 nm
respecti vely.
References:
1. T.V. Venktachalam and A.S. Rao - ibid
2. L.R. Jakobsson: Ark.f.Fys. 34, 19 (1967),
Table 1: Assignments of Observed (2+1) REMPI spectra of S atom
excited from 33*3?* *D2 level.
• ExcitationWave- Wave-
2 Phot-on en-
length number ergy*air (vacJa
(nm) cmcm
Excited StateConfig Term
Desg
Energy LevelObser- Refer-
J ved ence2hP (3)
288.094 34700.7 69401.4 3s23p3(2D0)4p
288.845 34610.5 69221.0
288.965 34596.0 69192.0
289.045 34586.6 69173.1
289.93') 34479.9 68959.8
290.111 34459.5 68918.9
290.136 34456.5 68913.0
291.145 34337.1 68674.2 3s23p3(4S0)6p
291.176 34333.4 68666.8
291.216 34328.7 68657.4
291.385 34308.8 68617.6 3s23p3(2D0)4p
291.396 34307.5 68615.0 3s23p3(4S0)6p
291.414 34305.4 68610.8
291.53 34291.8 68533.6 3s23p3(2D0)4p
4p F
4p3F
4p3D
6p3P
4p!P
6p5P
1D
3
4
3
2
3
1
2
1
0
2
1
2
1
2
78640.02
78459.6
78430.6
7841l'.7
78198.4
78157.4
78151.6
77912.8
77905.4
77896.0
77856.4
77853.6
77849.8
77822.1
78839.9
78463.04
78435.81
78409.89
78203.18
78152.34
78152.07
77913.54
77902.21
776"ft. £.3
77854.9
77853.23
77850.74
Vacuum wavenumbers taken from Table of Wavenumbers Vol. 1,
C D . Coleman, W.R. Bogman, W.F. Meggers, Natl. Bur. of
Stds.,(1960).
Two photon excited intermediate state energy calculated by
adding to the two photon energies, the energy of 3*D2 state
w.r.t. ground level (9238.6 cm ref. [3bJ).
-11.'.
155
m
5
o
o
uV \
280 1 268 9 269 OB 2B9 05 290 12
— USER WAVKLKNCTJl.nm-— .
V)
a•N
a
to
N
a.a.
Oi
cuCk.
a.o•
euna.
2f)2 291.5LASEH WAVELENGTIl.nm
- 1 2 3 -
2. 5- 12
LASER POWER DEPENDENT STUDCS IN MULTLJPHOTON ION&ATION OF BA
S.G. Nakhate, S.A. Ahmad, M.A.H. Razvi and G.D. Saksmnm
We have observed '.wo new resonances at S73.75 and 575.819 nm
in our studies o-f four—photon ioni Ration of Ba*. These
resonances could not be assigned to any Ba I level below the
•first ionisation potential. The excitation spectrum at these
wavelengths suggest that these resonances are due to autoionising
states, as we did not see any Ba neutral fluorescence.
In order to unambiguously assign the number of photons
required to reach these resonances we have carried out the
following laser intensity dependent studies. The fluorescence
intensity <Ir) of D4 line of Ba* <6p *P9s2 • 6s *S^2) was
monitored as a function of laser intensity (1^). Theory of
non-resonant multiphoton ionisation state that, for n-photon
ionisation the probability of ionisation is given by.
Pn —• probability of n-photon ionisation
&n —» cross section of process
Ic —* laser intensity
i.e. log Pn = log £>•„ + n log It <ii)
Figure 1 shows these log Ir vs. log IL plots for various
excitations. As expected we get a slope ^4 (Fig.la) for
non-resonant four—photon ionisation of Ba at laser wavelength
597.0 nm. Laser intensity dependent studies at resonance S73.75
nm shows the slope ~2.97 (Fig. lb); this wavelength the
ionisation is a resonant process, the slope of ""3 indicates that
the newly observed autoionising state lies at four-photon
absorption position. This new autoionising state is expected to
lie at 4 x 17429 cm'1 =• 69716 cuf1 above ground state of Bal
(First ionisatioon potential of Ba •= 42302 cm"*).
Reference:
1. S.G. Nakhate, M.A.N. Razvi, S.A. Ahmad and G.D. Saksena;Spectroscopy Division Progress Report for 1989-90 (To bepublished).
<0 ~ 1 Z 5 ~
T
u0
- U f c -
2.5.13
STUDY OF ROLE OF COLLISIONS »J MULTIPHOTON IONISATION OF BA
S.G, Nakhatm, S.A. Ahmad, M.A.N. Razvi and 0*D. Saksmna
The present study is an extension of the work which was
reported earlier* on multiphoton ionieation (MPZ) of Ba using
tunable pulsed dye laser. In the MPI studies of Ba we hava
observed1 the four—photon ionisation of Ba resulting in the
population of 6p 2Pt/2,i/i levels of Ba* and monitored via the
fluorescence of D4 (6p ZPa/x ——* 6s
2St/2) and Dz(6p Pt/l ——» 6s
81//a) lines of Ba*. Presently we have carried out the studies
on fluorescence intensity dependence of Dt and D 2 lines on the Ba
atom number density. (Ba atom number density has been determined
from the measured oven temperature using tabulated vapour
pressure data by Nesmeyanov ). The intensity of D4 line <Ir> was
monitored as a function of Ba atom number density (N). The
values of Ir are plotted as a function of N in the log-log seals,
which shows linear dependence with slope **1 (Figure 1). The
observed linear dependent relationship signifies that the
collisional effects are negligible in our working number density
region (T" 675°C). The population of 6p ZP level of Ba* due to
collisional process would have resulted into the slope 2. These
studies leads to the conclusion that the population of Ba* in 6p
P levels is due to the autoionising decay of Ba atom after a
minimum of four—photon absorption and not due to the various
collisional process such as excited atom-atom, or atom-ion,
ion-ion collisions. As can be seen from Figure 1 at higher
densities of Ba atom <>104* atoms/cm*) the collisional effect*
coaes into picture as evident from the slop* of the curve. i»fe
have also observed the fluorescence lines of neutral Ba atom
which is the result of collisional transfer to various energy
levels at higher oven temperature. So for all our studies on MPI
of Ba, we have fixed the working temperature at 67S°C which gives
collision free environment.
Referencest
1. S.G. Nakhate, M.A.N. Razvi, S.A. Ahmad and B.D. Saksena,Spr.ctroscopy Division, Progress Report for 1989-9B <To bepublished).
2. An. N. Nesmeyanov, Vapoour pressure data of elements, p4S8.
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- m-2.5.14
SETTMO OF A RESONANCE JONCZATION MA9S SPECTROMETRY FAOLITV FOR
THE ULTRA TRACE DETECTION OF SHORT-UVED ISOTOPES.
A. Venugopalan, Pushpa H. Rao, S.G. Nakhate, S.A. Ahmad and
G.D.Saksena
In the recent years, the laser based investigation of
short-lived isotopes of heavy and medium heavy elements has
provided valuable information about the nuclear properties of
these elements. Such neutron deficients isotopes (or neutron
rich) ar& being produced at the Pelletran facility and the
nuclear reactor facilities. As the production yield of these
isotopes are very very small (of the order of (<10 atoms), an
extremely sensitive, efficient and selective (both elemental and
isotopic) method of analysis has to be employed for their
quantitative estimation. Resonance Ionization Mass Spectrometry
(RIMS) ideally meets these requirements C13. Hence, a project
has been taken up to set up an RIMS facility for the ultratrace
analysis of such samples, both from the Pelletron facility as
well as the nuclear reactor facility for initiating high
resolution spectrascopic studies on the isotopes and isomers of
our interest. The proposed RIMS set up is schematically shown in
Fig.l. It consists of:
(i) A thermal atomic beam source which provides a steady beam
of the sample atoms. The oven can be heated to a
temperature of "" 20B0°C by resistive heating. This is
designed for handling relatively large sample sizes. A
confined cavity type source for very small sample sizes is
- 150-
also being designed.
(ii) Capper vapour laser (CVL) pumped dye-laser system,
consisting o-f two or three dya lasers depending upon the
specific case. The combined beam from the dye lasers is
•Focused to the interaction zone, where the lasers
resonantly interact with the sample atoms carrying out
stepwise excitation and subsequent ionization. High
elemental selectivity is achieved this way. Efficiency of
resonance ionization depends on the duty cycle which is the
product of laser pulse repetition rate and time of flight
of the atoms. The high repetition rate of CVL <>6 KHa)
provides a high duty cycle and hence a high efficiency for
the method.
(iii) The Time of Flight (TOF) spectrometer which provides the
. mass analysis of the resonant ions. The high resolution of
the TDF spectrometer O300) guarantees isotopic selectivity
in cases where the isotope shift is not sufficiently large
to achieve this selectivity at the excitation & ionization
stage. The reflector type bent geometry of the TOF
presently designed saves the detector from the
radioactivity of the samples under study.
The CVL is expected to be delivered from CAT, Indort* soon.
The design of the three parts of the RIMS discussed above has
been completed and they are now at various stages of fabrication.
Reference
1. V.S. LetakhovLaser Photoionization Spectroscopy, Academy Press Inc.vOrlando (1987).
-131 -
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2.6.1
PROGRESS REPORT ON THE BEAM LINE FOR PES OF SOUDS AND OASES IN
INDUSH
S.V.M. Bhaskara Rao and P.S. fturty
Details of vacuum component* ate. required for the beam line
The beam line for PES needs to be UHV compatible in order
to safeguard the UHV environment of the storage ring and also
prolong the performance of the optical components. The schematic
of the beam line showing the various vacuum components is
illustrated in Fig.l. The three chambers in which the pre—mirror
<Mt), gratings (6) and the post-mirror <M2) will be mounted need
to be leak-proof with a maximum leak rate of 10~*° Torr.
litres/sec. The vacuum pumps which are to be incorporated in the
beam line should be oil-free type. On the basis of these
considerations the requirements of vacuum pumps and vacuum
components have been worked out. A turbomolecular pump (TMP) of
100 1/s capacity will pump down the system to 1B~ Torr. The
three chambers will be connected to the TMP with all-metal valves
(4>. Due to the bigger volumes of lit and G Ti sublimation pumps
(5> will be used in addition to the sputter—ion pumps <I1,II,IA)
to ensure UHV in these two chambers. The volume of Mj is
relatively small and hence a sputter—ion pump (I,) of 70 1/sec
capacity will be adequate to obtain UHV. The Ti sublimation
pumps will also help in taking the excessive outgassing load
during bake out at 258°C. UHV gate valves (1) will be provided
to isolate each chamber as and when required. UHV compatible SS
bellows (2) with welded CF flanges (114 mm dia) will be
incorporated at appropriate places in the beam line. Pressure
measurements will be made with a convection type Pirani gaulge
(6) and B.A. nude type ionization gauges (3). In Table 1,
approximate volume and surface area of various sections which are
to be pumped down are given.
Table 1: Volume and surface area of different sections in the P'ES
beam line
Section Volume
(litres)
3B
38
9.8
7
7.7
13.5
2
Surface are
<sq. mts>
0.63
0.63
0.25
0.40
0.44
0.77
0.11
Mi
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BS2
{.Z-&-1J W«. 1. Sch««atio of the PES B«ert«*e illurtratlng th. T.CUU. component.
- 135"-2.6.2
HH3H RESOLUTION VUV SPECTROSCOPIC FAOLITV AT INDUS-I
G. Krishnamurty, Saras fiat hy Padmanabhan, P. Meenakshi Rmja Rao
and A.P. Hishra
The 450 MeV Storage Ring INDUS-1 at Centra for Advanced
Technology (CAT), Indore is going to be a valuable Synchrotron
Radiation Source (SRS) for Vacuum Ultraviolet (VUV) Spectroscopy.
One of the beam lines will be dedicated to carry out
photoabsorption spectroscopic studies of atoms and molecules
under high resolution in VUV region. Some of the details of the
design and development of such a beamline which will be built at
INDUS-I ars presented in this report.
There are only two places in the world where high
resolution OX.5 x 10*) VUV spectroscopic facilities arm
available. One is at Photon Factory (Tsukuba, Japan) and the
other at SURF II (Gaithersburg, USA). Some of the salient
features of these two facilities were reported by Ginter (1).
Having exammined the various aspects of these two beamlines and
taking into consideration the needs of the user community, we
have been able to develop a tentative design of the high
resolution <HR) VUV facility at INDUS-I. This is expected to
provide resolving power of the order 10s or better in the normal
incidence region (300-2000A). All the details related to the
development of the beam line have been brought out periodically
in the form of status reports "Synchrotron Radiation Source
Utilization - SRSUT-1 to 6 <2)".
-JS4-
Fore-Optics
The HR beam line will consist of a fore-optics which will
-focus the Synchrotron Radiation from the tangent point of the
storage ring onto the slit of the HR spectrometer. The
experimental area provided in between the fore-optics and
spectrometer is intended to insert suitable absorption calls
depending on the types of studies that the user is going to
undertake. The top view of the beamline is shown in Fig.l. The
•for-e—optics consists of three cylindrical mirrors coated with
osmium or gold. The choice of radii and the size of the three
mirrors depend upon the horizontal and vertical divergence of the
SR beam and the distance between the tangent point and the first
mirror of the fore—optics.
Our first task was to decide the horizontal divergence
needed to carry out HR photoabsorption studies. In order to
arrive at a figure we have made a comparative study of the flux
and spectral brightness of INDUS-1, SURF II and Photon Factory.
Results of these calculations are presented in Table 1 and th«
flux distribution plots showing the variation of photon flux with
wavelength is shewn in Fig.2. These studies enabled us to
conclude that horizontal divergence in the range 30-60 mrad is
good enough for the type of studies that are planned in the beam
line. If the first mirror is kept at 2.5 metres from the tangent
point due to constraints imposed by the accelerator group, a
horizontal divergence of 50 mrad is suitable for the proposed
studies. Once the distance from the tangent point and the
horizontal divergence are fixed* the mirror size, beam pipes, and
the UHV components can be fined. Since these cylindrical mirrors
need special coatings and good surface finish several agencies
Mere contacted -for the supply. li/s. Jobin Yvon (France), M/«.
Baker (USA) and M/s. Tucson (USA) have come forward to supply tha
mirrors to our specification. The relative positioning of tha
three mirrors depend upon the nature of the H.R. spectrom' >r.
It is now more or less certain that a 6.65 M spectra ater in
Eagle mount will be used in the beam line. More details about
this instrument can be seen in a later part of this report.
UHV Requirements
Since the order of vacuum in the storage ring is 161 torr
it is necessary to maintain the same vacuum in the beam line. In
the experimental area, differential pumping facility has to be
provided to handle higher gas loads for carrying out experiment*
in windowless region (below lBBBA). The vacuum required in tha
HR spectrometer is of the order of 10" torr. Based on these
requirements, the pumping speed for the entire beam line was
calculated (3) and various types of pumps that are to b»
installed in the beam line has been decided. A list of these
pumps required is given in Table 2. The TPPEO of BARC and CAT,
Indore are in a position to supply Ian pumps and most of tha
vacuum components required for the beam line. More details can
be found in SRSUT-6 (2).
Frame Work
In collaboration with CWS of BARC a tantative sketch of tha
framework to house the mirror boxes and beampipes of the
fore—optics was preparead. Side view of the -frame work is shown
- IS?"in Fig.3.
HR Spectrometer
Having examined the requirements for carrying out HR VUV
spectroscopy, we have decided to acquire a 6.65 metre
Spectrograph cum Spectrometer in 0-ff-plane or In-plane Eaglet
Mount. This is a versatile instrument to meet the requirement in
the normal incidence region. An indent was placed and quotations
were received -for building such as instrument -from M/s- Acto.m
Research Corporation (USA), M/s. Chelsea Instruments (UK) and
M/s. McPherson (USA). After scrutinising these offers it has
been decided to fabricate certain components like vacuum tank
etc., indigenously to reduce the import cost considerably.
Efforts are in progress to finalise the offer. In collaboration
with CW3, we are exploring the possibility of fabricating the
vacuum tank of 80 cm diameter and 8 mm thick to hjuse the grating
assembly scanning mechanism and camera chamber.
Vibrationless pillar
In order to achieve full resolution, it ie essential to
mount the HR spectrometer on vibrationless piers. It is proposed
to design and fabricate vibrationless pillars indigenously making
use of the expertise available in the division. The Seismology
Section of BARC is associated in our efforts to build suitable
vibrationless pillars.
References:
1. M.L. Ginter, Nucl. Instru. and Meth. A246. 474 (1986).
2. High resolution VUV spectroscopic facility at INDUS-1. Beamline Instrumentation, INDUS-1 < Utilization Report
SRSUT-1 Oct.1988
SRSUT-2 Jan.1989
SRSUT-3 June 1989
SRSUT-4 Dec.1989
SRSUT-5 May 1990
SRSUT-6 Dec.1990
Balzers Catalogue - Pfeiffer Turbomolecular pumps. VacuumTechnology (1988).
3.0 m
1.7 m
6.5 m
MIRROR BOX 1
MIRROR BOX 3
FRAMEWORK FORFORE-OPTICS
1
21.5 m
3.0 m
T-1 FLANGE
I
^ H L " fcM)r -B T-LBTI e
MIRROR BOX 2 *
PUMPING STATIONS
EXPTL_AREA
7.0 m
VIBRATIONLESSBASE
VACUUMTANK
6.6 m SPECTROMETER
2.0 ra
WORKING!SPACE I
Sp
0 1 2 meters
SCALE
TOP VIEW OF HIGH RESOLUTION VUV BEAMLINE(£. i Z)
t1
10"
10"
10"
PHOTON FACTORY
: INDUS-
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100100
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FIG-2: SPECTRAL FLUX COMPARISON OF SURF-M, HMOUS-1 AND PHOTONFACTORY.
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Spectral Flux Comparison of INDUS-I, SURF and Photon Factory
Flux NO-)iPhotons/sec/mrad-0.IX Band Width
No. of mrads (horizontal)of INDUS-I which gives asmany photons/sec-0.IX B.W.
TNDUS^T SURF^II Photon Factory 60 mrad of 5 mrad of5URFII Photon Factory
300
500
1000
1500
2000
2500
3000
1.0x10"
9.4X10*1
8.0x10"
7.3x10**
6.8x10**
6.3x10"
6.0x10"
5.5x10**
6.3x10**
6.3x10**
5.9x10**
5.7x10"
5.4x10**
5.2x10**
6. 8x10**
6.0x10**
5. 1x10**
4. 6xl0*2
4.3x10**
4.1xl0*2
3.9X1012
33.0
40.2
47.2
48.5
50.3
51.4
52.0
34.0
31.0
31.9
31.5
31.6
32.5
32.5
TABLE 2
UHV REQUIREMENTS FOR HIGH RESOLUTION VUV BEAM LINE
I. PUMPS
1. Fore-Optics
Location Nature of Pump peed Vacuum(torr)
Pumping StationA
Mirror Box1
Mirror Box2
Mirror Box3
Pumping StationB
Turbo-Molecular PumpingStation (Magnetic Suspensiontype, Hydro Carbon free)
Ion Pump
Ion Pump
Ion Pump or Cryo Pump
Turbo-Molecular PumpingStation (Magnetic Suspensiontype. Hydro Carbon free)
10001/sec 10"*
5001/sec
5001/sec 10"*
10001/sec 10"p
10001/sec
2. Spectrometer
Main tank
Camera Chamber
Diffstak or Turbo MolecularPumping Station
Turbo Molecular pump
20001/sec 10"7
2501/sec 10~7
3. Experimental area
Absorption cell 2 nos. of diffusionpumping stations
5001/sec.
2.6.3
DESIGN AND EVALUATION OF PES BEAMLINE OPTICS
N.C. Dm* and B.N. Rajm Sukhmr
A bwamline for PES of solids and gases is being developed
at INDUS-1 (450 MeV) at CAT, Indore <1). This beamline works in
the wavelength range of 50A - 400A. Ac the reflectivity in this
energy rang* is low minimum number optical components oriented to
have large incidence angles are used. This beamline therefore
tuffer from astigmatism predominantly resulting in the elongation
of spectral image and loss of spectral flux due to finite
•ntrance and exit slits. For canrolling these problems
efficiently two toriadal mirrors and a toriodal grating as a
dispersing element have been used in this beamline.
The evaluation of the beamline parameters such as vertical
and horizontal acceptance angles, length, breadth, radii of
curvature of the mirrors and gratings was carried out in a
comparitive way between two models namely TGM-3000 and TGM-1400
<2> . From the layout resolution and photon flux at the sample
point has been evaluated respectively. TGM-3000 Mas found to be
preferable for optimum spectral resolution and photon flux.
From the information obtained regarding the availability of
the componcmts of the beamline it was found that procurement cost
could be reduced by considerable amount if off-the-shelf
components are used. The specification of theee components were
slightly different from those finalised by the preliminary
optical layout. Therefore the layout has been modified to match
the available (off-the shelf) components for both the systems
(TGM-1400 and THM ^,000). It was found from recomputation that
spectral intensities did not change much compared to the
preliminary calculation. A* the selection of TGM-3000 is more or
-Wt-less final work will be continued to evaluate the estimation of
the image blur by actual ray—tracing procedure. Table 1 and
Table 2 gives the spectral flux and resolution at the sample
point and Figure 1 and Figure 2 gives the layouts using T6M 1400
and TQM 3000.
References:
1. Inda-USSR Seminar on Synchrotron radiation source,Jan.30-Feb. 3, 1989
2. Beamline Instrumentation INDUS-1 utilisation. ReportSRSUT-5, May, 1990
3. Beamline Instrumentation INDUS-1 utilisation, ReportSRSUT-6.
Table It Spectral Resolution and Intensit ies for thiBeam Line using TGM-300125 (modified system)
Entrance s l i t width = 100/um
ot,, = 12 mrad, a = 10 mracS
"mi "
\A
50
B0
100
180
200
360
7.0 «rad, Vmi
AXA
0.026
0.030
0.052
0.060
0.104
0.120
•= S.S5 mrad
IntensityPhotons/sec
1.65 x 10*°
1.90 x 10***
3.03 x 10***
2.11 x 10*°
3.33 x 10***
2.03 x 10*°
Table 2i Spectral resolution and intensities forthe beamline using TGii-1400 (modifiedsystem)
Entrance slit width - 20 nm
a,, » 20 inrad, a « 11.73 mrad
Umv - 8.92 mrad, U ^ - S.23 mrad
X AX IntensityA A Photons/sec
5 0
9 0
100
180
200
3 6 0
0.061
0.063
0.076
0.256
0.287
0.319
4.50
4.63
5.15
10.47
10.67
6.26
X
X
X
X
X
X
10to
•10*°
101 0
10*°
10*°
10to
\
SIDE VIEW125 mm
P U N
TOROIDAL MIRROR
TOROIDAL GRATING
TOROIDAL MIRRORV79i
s
VH,
(U 1) F1G.1. PES - BEAMLINE USING TGM-3000
SIDE VIEW
TOROIDAL MIRROR
P, -
TOF.O1DAL GRATING TOROIDAL MIRRORR, = j444a'ni"3 S O
PUNv»nG.2. PES - BEAMLINE USING TGM-1400
2.6.4
DESIGN AND EVALUATION OF HIGH RESOLUTION VUV BEAMI.INE OPTICS
N.C. Das and B.N. Raja Sekhar
Using eynchrotron radiation from INDUB-1 (45B MeV) A
Beamline for high resolution spectroscopy of atoms and fficilecules
is being developed <1) covering a wavelength range of 40(8-25(311 A.
This beamline contains a three cylindrical mirror for»-optics
system for matching the radiation of rectangular aperture to
6.0/6.65 M off-plane eagle mount spectrograph/spcctrometer with
20 mrad (Horizontal) x 20 mrad (vertical) acceptance angles.
Taking into consideration of the different parameters which play
important role in the optimisation of the Beamline optics,
computation of the layout and development of the ray-tracing
program was been done '2). Using the layout parameters and
Ray-tracing programme the design has been finalised by analysing
the results obtained (3) (4) as shown in figure 1 and figure 2.
Table 1 gives the intensity at the image point of th»
spectrometer/spectrograph.
Table li Spectral intensity o-f high resolutionVUV beamline
Source size: 1 mm x B.1 mm
Spectrometer slit width = IB micrometer
Spectrometer acceptance angle =
20 mrad (Horizontal) x 20 mrad (vertical)
Spectral Band widths A\ • 0.004 A
\ IntensityA Photons/sec
400 20.7 x 10*
600 14.3 x 10a
800 7.5 x 10*
1000 5.2 x 10*
1200 4.3 N 10°
1400 3.9 x 10B
1600 3.8 x 10*
1800 3.3 x 10*
2000 3.0 x 10*
References1
1. Indo-USSR Seminar on Synchrotron Radiation source, Jan 30 -Feb. 3, 1989
2. B.H. Spencer and M.V.R.K. Murty, J. Op. Soc. AH 32, 673(1962)
3. Beamline Instrumentation INDUS-1 Utilisation, Report No.SRSUT-5, May, 1990
4. Beamlin* Instrumentation INDUS-1 Utilisation, Report No.SRSUT-6.
- 153-
1
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P1«« 2 9p«otral blur at th« entrance slit
2.6.S
BEAM-FOIL SPECTROSCOPY
P. Meenakshi Raja Rao, A.P. Hishra, Sarasnathy Padmanabhan *nd
G. Kr ishnamur ty
1. Beam-fail Spectrum of Argon:
Beam-foil spectroscopic investigations of Argon are cani*d
out in collaboration with T.I.F.R using a 400 KeV accelerator.
"• le spectrum was recorded at different energies ranging from 160
to 320 KeV in the wavelength region of 2800-5000A. The
experimental set-up used in the present studies has been
descrilbed earlier (1). A microprocessor controlled data
acquisition system was developed for recording the spectra. The
acquired data was then transferred to a Personal Computer wherein
two or more spectral scans can be added if necessary and the
spectra were plotted. This technique facilitates signal averaging
which improves signal to noise ratio and yields goad quality
spectra. Such a facility contributes significantly in recording
weak spectral lines and in collecting data for life-time studies
with good statistics.
Fink et al (2) reported the wavelength spectrum of Aril and
Arlll in 3300-5000A region and also the mean radiative life times
of some of the excited energy levels. In their experiments Ar*
beam in the energy range of 10(9-600 KeV was used and the spectra
were photographed at a dispersion of 83A/mm. Subsequently,
Coetzer et al <3> reported beam foil spectrum of Aril in
2000-5000A region using a 5 MeV Van de Graff, the main emphasis
of their studies being life-time determinations.
- Ufc -
In the present studies, the beam-foil spectrum of Argon was
recorded on a half—meter monochromator in Czerny—Turner mount at
a dispersion of 16A/mm and a resolving power of 1.5A, using a
Peltier cooled photomultiplier and photon counting system. This
technique is more sensitive compared to photographic technique.
Thus it was possible to observe a richer spectrum of Aril and
Arlll with good intensity. The beam foil spectrum of Argon in
the 3400-3650A region recorded with 280 KeV Ar* beam is shown in
Fig.l. It was observed that some of the spectral lines involve
high 'n' and '1' valules like 4f, Sf, 6f and 7f states. These
lines exhibited greater intensity compared to those observed in
standard laboratory sources which is a unique feature of
beam-foil excitation.
2. Target-Ion Chamber:
The fabrication of a target ion chamber for beam-foil
spectroscopic investigations of lifetimes and atomic and nuclear
polarization studies is in progress in Central Workshops, DARC.
Fig.2 is the side view of the target chamber. The movement of
the lead screw which drives the foil assembly is controlled by a
stepper motor with a smallest step size of 25 microns which
provides a good time resolution for life-time studies. The foil
assembly is also provided with a facility to mount the foils at
different angles to beam axis for polarization studies. A turbo
molecular pumping station of 480 1/s pumping speed is being
procured to evacuate the chamber to a pressure of ""10 torr.
R»ferencesi
1. P. Meenakshi Raja Rao, 6. Krishnainurty, S. Padmanabhan andB.N. Rajasekhar, Bpectroscopy Division Progress report,BARC-1481, 54, 19B7-BB.
2. U. Fink, S. Bashkin and W. Bickel, J. Quant. Spactrosc.Radiative Transfer JU0, 124, 1970.
3. F,J. Coetzer, T.C. Kotze and P. Van der Wasthuizen,J. Quant. Spectrosc. Radiative Transfer, 3j3, 253, 19B7 and59, 181, 198B.
-158-
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2.6.6
RF.INVFftriOATION OF SOME OF THE AUTOtONIZINO LNES OF Cul
SarasHjthy Padmanabhan, P.Meenakshi Raja Rao and G.Kr ishnamurty
Th<=> spectrum of neutral copper provides an interesting
example t»f autoionization and perturbations. More than half of
the discrete energy levels lie above the first ionization limit
(3d >. Spectral lines involving some of thsse discrete levels
show anomalous broadening due to autoionization effect, because
of their interaction with the continuum. The present studies
deal with line broadening of spectral lines involving 3dP4s5«
con-figuration which gives rise to 5s* V?/g,s/z,a/a,ts* * 5 s #
" -and 5s" nr> 2,»/2 levels. All the spectral lines
involving these states lie in visible-UV region. The
experimental details of generating and recording the spectra and
evaluation of half widths from line profiles were reported in
Bpectroscopy Division Annual Progress report (1).
A critical evaluation of the half widths enabled us to
conclude that all the transitions involving 5s' DB/2,»/H 5 S '
*Ds^2.»^t a m l 5 s " tosyxrm^z a r B broad diffuse, while the spectral
lines involving 5s' *H-T/-ZA^Z levels do not show any broadening.
This is because of autoionization, the discrete levels with J
5/2 and 7-/2 interact with the continuum states having
character! 'tics of 2D of 3d*°Ed continuum, whereas the
interaction of levels with J = 7/2,1/2 is forbidden due to
electric dipolc selection rules (2). In order to show that the
contribution to the line broadening of diffuse lines is
predominantly from natural broadening, line profile studies were
undertaken. Different factors which contribute to line
broadening Are> natural, Doppler, Instrumental and Pressure
- Hi-affects. The profiles of lines due to natural and pressure
broadening follow Lorentzian distribution, while the Doppler and
Instrumental broadening follow Gaussian distribution. In order
to estimate the extent to which the above factors contribute the
line shapes of the observed lines of Cul were fitted to Gaussian
and Lorentzian functions
I. » Io exp - 2.772
i/"*1
- Io
1 * 4AX
Nhtre Iv is the intensity of line at wavelength X, Io the peak
intensity at X = Xo ths» central wavelength, AX1/aB and AXt^xL arm
the Baussian and Lorentzian halfwidths respectively. The
profiles were generated by calculating intensities I. from the
experimentally observed peak intensity IoT and the respective
half width AX1/X. The calculated profiles were then superposed
over the profile obtained from the densitometric profile.
The instrumental width was evaluated by recording a Fe line
from a Fe-Ne hallow cathode source. Fig.1 shows the profile of a
Fel line at 3B17.61A. It can be seen that the profile is mainly
Gaussian due to instrumental width since the Doppler contribution
is less. The instrumental width in the present experiments was
-found to be of the order of 0.45 cm*1 which can be neglected
compared to large observed width of the diffuse lines.
Having determined the instrumental width, the profiles of
Cul lines were examined in detail for the contribution due to
Doppler and natural broadening. Sharp lines of Cul arising from
5s' I>7 2,t/2 show Gaussian distribution, which is mainly from
Instrumental and Doppler effect. The contribution of Doppler
width was estimated to be 0.04A in 5000A region.
In the case of diffuse lines the profile tend to be more and
more Lorentzian as the Doppler and Instrumental contributions arm
negligible. These features can be clearly seen from Fig.2 where
Lorentzian and Gaussian distributions are superposed over the
experimental curves. De-convolution of the contribution due to
Doppler and Instrumental clearly indicate that the large line
width of diffuse lines of Cul is due to broadening of perturbed
levels *DS^2#8^1 ""a LS/-* affected by autoionization.
References:
1. P. Meenakshi Raja Rao, G. Krishnamurty, S. Padmanabhan andB.N. Raja Sekhar., Bpectroscopy Division Progress Report,BARC, 1989.
2. E.U. Condon and 6.H. Shortley., Theory of atomic spectra,Cambridge University Press p374 (1979).
Fel 3617.64 K
-AX./,= 0.07 A1/2
- LORENTZ1AN
• GAUSSIAN
— EXPERIMENTAL
{HOFIG. 1. PROFILE OF FU 3817. S M LINE FUOH FC Nfc" HOLLW
PHOTOGRAPHLO AT A 013PER510N OF 1.2SA/HH ANO 10K SLIT MOTH TO
DDWNSTKATE INSTRUMENTAL HWTH
UPPERSTATE 5s' 4 D l / 2
A(A) 4248.96
r -FIG.2. EXPERIMENTAL PROFILES OF SPECTRAL LINES OF CUI INVOLVING
35 *0 MULTIPLET COMPONENTS AS UPPER STATES FITTED TO LORENTZIANAND GAUSSIAN DISTRIBUTIONS
- EXPERIMENTALx LORLNTZIAN• GAUSSWf
3. 1.1
SIGNAL DETECTION AND PROCESSING FOR ICP SPECTROMETER
P.K.S. Parakis a Rao, S.V.G. Ravindranath and M.N. Patil
In continuation of the work rsported in the Division
proqrtsi report for 1987-86 <BftFtC-i481, pl41-143, 1989).suitable
hardM*rn and software have been developed and tested to increase
the dynamic range of the measurement of the signal detection
r.ystem employed in ICP Spectrometer. The hardware consists of a
comparator (LM 339), a uni multi (74121), decoders (74LS138), hex
inverter* (74LB04), AND gates (74LS08), tri state buffers
(74LB125) and an I/O card containing PPI chips (B255). The block
schematic of the signal detection and processing for ICP
spectrometer is shown in Fig.l. A software program developed in
Microsoft Quick Basic to collect the data from all seven channels
by initiating the ports of PPI chips, and monitoring sequentially
whether the integrating capacitor of each channel has overflown
or not, and if so, it digitizes the capacitor voltage with the
help of an ADC and updates the count, discharges the capacitor
and repeats the process for all channels till the end of the
exposure period.
The dynamic range improvement is obtained by monitoring the
charge stored in the integrating capacitor and preventing it from
over loading by periodically monitoring the capacitor with
hardware under program control. During interrogation, if the
capacitoor output voltage exceeds the reference voltage of the
comparator, overflow signal will be generated by the comparator
which sets a flipflop of 8255 operated in mode 1. Then the
- JU -program sends a convnrt command to ADC and digitizes the
intagrator output, stares it in the memory and discharges the
capacitor or else it proceeds to the next channel to perform the
similar operation till all the channels are read sequentially.
The performance of the data acquisition system is tested by
calculating the standard deviation, which mrm shown in the table
below from a set of ten readings taken for different currents
supplied from a curren source in the range 10~*A to 4.43»10'<*A.
TABLE li Reproducibility data of the acquisition system
using a currant source.
10*A
340
342
341
343
341
341
341
341
343
340
X8TD 0.310X
10~*A
3171
3177
3170
3178
3176
3178
3175
3173
3176
3178
0.076X
10~7A
33491
35521
35462
35432
35462
354B8
35484
35422
35413
35486
0.097X
4.43»10"0A
1331950
1334119
1332243
1331798
1334025
1333950
1333914
1331644
1332076
1333B4
0.081X
The standard deviations observed using D.C. arc with graphite
blank for the elements Mn, B, Cdf Mg, Crf and Ni mrm shown in the
table below.
Table 2i Raproducibility results of the signal detection systm
of the ICP Spectrometer with D.C. arc excitation source.
XSTD
Mn
34046
39150
37B22
36650
39397
37295
39337
3G066
3S153
39189
4.4X
B
35S35
41312
40955
402 IB
42236
41456
42361
4233B
41B82
42291
2.9X
Cd
52024
50077
51428
54244
53148
527Q2
52306
52478
54140
31933
2.367.
Mg
14930
16233
17179
15985
1B436
19840
16607
161
16495
16497
8.19X
Cr
52773
56836
S5729
55340
57500
57052
58497
58741
5881S
57889
3.3X
Ni
26376
29296
27B31
25200
27643
26624
27967
27672
26125
28706
4.56X
I
. i BLOCK SCHEMATIC OF THE SICNAU CET£CTICMAND
• - J C T -
3 . 1 . 2
INSTRUMENTS MAINTAINED AND SERVICEDH.C. Goyal, H.N. Pati1, Rajiv Sinha, Sampat Kumar, Hanika Das,
S.V.G. Rav indr anath and P.K.S. Prakasa Rao
During this period the electronic portion o-f Per kin-Elmer
IR Spectrometers models 180,21, ARL Quantovac model - 31000,
Raman Spectrometer (1401), with an Argon-ion Laser, Philips X-Ray
Spectrometer, Hilger £ind Watts X-Ray Generator Model Y-fe0,
TCP-Spectrometer, Jarrel-A-sh Comparator Modei-23-500 large quartz
spectrometer and also Jaco custom vari source, Barocel pressure
sensor type-600, digital pressure display and pressure sensor
type-1500, Ithaco lock in amplifier model - 391A, EG&G wide band
pre amplifier model-115, temperature controllers, electro meter
amplifiers, microwave power generators 100 watts and 200 watts,
pi rani and penning vacuum gauges, Hilger and Watts non—recording
microphotometer, recorders, power supplies were serviced and
maintained.
A PMT socket for EMI-981B tube has been wired and moulded
using Sylpot-10 dand metraark-13 catalyst material and tested to
replace the defective one. This PMT is used in the Raman
spectrometer.
The DC arc source belonging to high temp material section
o-f metallurgy division was pat into operation and tested for its
performance upto 25 amps o-f arc current.
- l / o -
4 . 1 . 1
INTERFACING OF RECORDING FABRV-PEROT SPECTROMETER WITH PERSONAL
COMPUTER
S.G. Nmkhate, S.A. Ahmad and G.D. Smksmna
The line shape fitting and deconvolution of complex
structure spectral lines is of great help in resolving small
hyperflne structures and isotope shifts) and also useful in
pressure and temperature broadening studies of the spectral
lines. In order to do this the recording of the optical signal
has to be In digitised form. With these studies in view, we have
completed the Interfacing of our Recording Fabry-Perot
spectrometer (REFPOS) with PC. The analog signal from the
photomultilplier is fed to the electrometer amplifier which is
then digitised using the Digital multimeter (Keithlers* Model
197j with IEEE-4BB interface). The digitised signal is made
compatible to PC using GPIB card as an interface. The necessary
software for the data acquisition as well as handling has been
developed with the help of Computer Division. The software was
successfully tested to record and display the grating as well as
Fabry-Perot <FP) spectra on the PC. The software allows to get
the mean of the distances between the different orders of FP
fringes and it is possible to have the horizontal as well as
verticle expansion of the spectrum.
Isotope shift data in digitised form is much more easy to
handle than the data on the chart paper. It will save our time
in finding the mean of the distances between the centre of the FP
fringes.
4.1.2
MACHINE SHOP ACTIVITES
H.B. Guhagarkar and H.H. Dixxt
During the period workshop has designed and fabricated
-following precision instruments.
1) Resonance Ionization Spectrometer with Time of Flight Ma**s.Spectrometer Device.
Resonance Ionisation Spectrameter is being set up in the
division. It will be used -for Ultra Trace Analysis of
elements using the technique of Resonance Ionization
Spectroscopy. The -following accessories have been designed
and fabricated,
a) Analytical Chamber and Evaucation System Accessories
The main body of the chamber is 8"I.D. and 8i/aM O.D
and 12" in length with Flanges at both the ends. It has got
B nos. of ports around the centre of the electrode Assembly
where Atomic beam and Laser beams interact. There arm two
ports diagonally opposite for the Laser in and the Laser
out. There are 2 nos. of oven ports at 43 to each other.
There are 4 nos. of viewing ports, 2 nos. mra for
measurement of oven temperature, and 2 nos *rm for having
clear view of the interaction zone. The ov«n ports are
having additional small chamber protruding inside th«
chamber for isolation of vacuum. For vacuum isolation th« -
oven chambers are closed by a flap and lcvsi—mechanise using
Wilson Beal technique during change of sample. Panning
gauge head port has also been provided. Th« one »id« end
flange having 5 nos. Df ports for feed through* and
evacuation port at the centre, is fastened to the main
chamber flange with bolts and nuts. Other side end flange
havinQ port at the centre for TQF Electrode Assembly os
fastened to the main chamber flange with bolts and nuts.
The one side of the chamber, the evacuation system is
mounted with extended tube, elbow and couplrd to the
Diffusion pump. One metre long TQF Drift tube along with
Electrode Assembly is mounted on the other end of the
Chamber. An additional evacuation system is connected to
the Drift tube near the Detector Assembly. For this
evacuation port a Liquid N2 Trap with isolation valve mrm
designed, fabricated and assembled ovear the Diffusion pump.
The Analytical Chamber has got 25 nos. of openings. The
vacuum testing of the entire unit is completed and it
attained the vac 1x10 " millibar. The whole assembly is
made out of 3194 S.S. and all the joints »ra made by means of
Argon arc welding.
b> The Low Temperature Furnace
It consists of a 304 S.S. crucible for sample, quartz
tube oven held between two copper caps which provide
electrical connections. This furnace is designed and
fabricated in a such way that it replaces the graphite
electrode of thp high temperature furnace so that same
assembly t ,*n be UHh-tl in t.ht> Analytical Chamber. This is to
be tip*?r <.»t t«d for Hit? temperature upto 60B°C for low melting
c) Time o-f Flight Mass Spectrometer
Time of Flight Spectrometer evolved in the recent past
as a powerful tool for the Trace Analysis because of its
versatality and ease with which could be adopted for the
various research requirements like Resonance Ionization Mass
Spectrametry and similar high sensitivity fields. The
various parts of the TOF arc like Electrode Assembly, Drift
Tube Assembly. Detector Housing. 5EM ION Detector is used
for this Assembly.
Fig. 1 A Front view of the Chamber
Fig. 2 Complete unit, Chamber with TOF Assembly
Fig. 3 End view, Feed throughs and Evacuation system
Fig. 4 TQF Drift Tube with Electrode Assembly.
2. High Temperature Superconductivity Thin Film Assembly.
A rotatable target for Laser ablated high temperature
material like YB2CuaD as well as rotatable substrate for
film formation have been designed, fabricated and tested.
A mount for the 1 rpm D.C. motor for rotating the sample
through the Wilson Seal has been designed, fabricated and
assembled on the Atomic Beam Assembly.
A similar mounting for 12 rpm D.C. motor for rotating the
substrate through Wilson Seal has been designed, fabricated and
assembled on Atomic Beam Assembly.
3. Accessories for BOMEM FTIR Unit
a) Low Temperature Cell
Designed and fabricated a Low Temperature Cell which
fits on the port of the Bomem FTIR Unit. This assembly is
being used for studying the sample at Liquid Na temperature.
b) Coupling for Bolometer
Designed and fabricated a coupling for Bolometer liquid
Helium transferring line.
c) Quick Fit Coupling for Liquid Helium Can
Designed and fabricated a quick fit clamp for liquid
Helium container to fit thle transferring line for
transfering the Liquid Helium from container to the BQMEM
FT1R unit.
4. A Device for Jarrel Ash Comparator
The scanning mechanism of the spectrum plate of Jarrel Ash
Comparator Mas damaged. Hence a device is designed,
fabricated and assembled on the unit using a pair of Teflon
Gears which yeilded a better—smoother scanning of the
spectrum plate than the original one.
5. Accessories for Long Path Cell
Designed and fabricated Long Path Cell's accessories such as
1) Mirror Housing Chamber, 2) Reflector Mirror and Detector
Housing, and 3) Bellow Housing to fit on the port of the
Bomem FTIR unit. The initial vacuum testing of this unit is
being carried out.
Qi-.LZ) F I G 2 : C O M P I - E T E U N J T - CHAMBER WITH TOF ASSLV.
7 7 --
(4.U) F l o i F.NH VII W F l l l > A i m f VA< I ' A I X . H : :v: : I I M
(Lie)
CDI
3. PUBLICATIONS
S. 1 P6|PERS_PUBLISHED_IN SCI^ENTXFIC JQURNALSIN199B
1. Three photon resonant ionizatior. in atomic potassium viaS,P,D and F series Rydberg states.A. Sharma, G.L. Bhale and M.A.N. RazviPrama (J. of Physics), Vol.35, 95 (1990>
2. Molecular emission following laser evaporation of copp**-aerosol.A. SharmaOptics Communication, Vol. 77, 303 <1990).
3. Isotope shifts in the energy levels of uingly ionizedsamarium (5m II) and electronic con-figuration* of oddparity levels.Pushpa It. Rao, S.A. Ahmad, A. Venugopalan and B.O. BaksenaZ. Phys. D15, 211 (1990).
4. Synthesis of 2-D thiazale and 2-D oxazole and formation ofpyrazine from reaction of oxazole.R. Venkatasubramanian and S.L.N.G. KrishnamachariInd. J. Chem. 29B, 562 (1990).
5. Rotational line strengths in the E - £ orbitallyforbidden electric dipole transitions.V.P. Bellary and T.K. BalasubramanianJ. Quant. Spectrosc. Rad. Trans., Accepted forpublication.
6. Line Strengths in A9£ - a£ Quadrupolc transition* withintermediate coupling: Application to line intensitiesin the quadrupolt? fundamental band of the oxygen molecule.T.K. Balasubramanian, Romola D'Cunha and K. Narahari RaoJ, ttol. Spectrosc. 144. 374 (1990).
7. Laser Optogalvanic studies of NHB in Dc discharg*.Kuldip Singh, Romola D'Cunha and V.B. KarthaOpt. Comm. Z2, 33 (1990)..
8. Laser Raman Spectra and Free and Restricted Rotation inphenyl silicates.M.N. Dixit, N.S.K. Prasad and V.B. Kartha.Proc. Ind. Acad. Bci. 102, 635 (1990).
9. Laser Raman and Infrared studiam on Hydrotrop»» andRelated Materials.8.B. Kartha, V.G. Baikar, M.M. Sharma and V.B. KarthaProc- Ind. Acad. Sci. 102, 681 U990).
juf,
IB. Laser Raman Spectroscopic studies on the interaction ofthe Drug Dapsone with Model Membranes.V.B. k'artha, N.D. Patel and S. VenkateswaranProc. Ind. Acad. Sci. 102, 697 (1990).
11. Release Studies of Atomic TechnitiumF. Ames, H.J. Kluge, E-W. Otten, B.M. Suri, A.Venugopalan, 6. Hermann, H. Rimke, N. Trautmann, R.Kirchner and B. EichlerIn print, Annalen Der Physik (1990).
12. Time dependent characteristics of a strongly driven Ramansystem underoing quantufm jumps.A.S. Jayarao, R. D'Souza and S.V. LawandePhys. Rev. A41. 1533-1543 (1990).
13. Photon statistics of resonance fluorescence in a squeezedvacuum.R. D'Souza, A.S. Jayarao and S.V. LawandePhys. Rev. A41. 40a3-40B6 (1990).
14. Quantum jumps in optical double resonanceR. D'Souza, A.S. Jayaraa and S.V. LawandeMod. Phys., Lett. 4, 813-821 (1990).
15. Temporal correlations of sidebands of the fluorescentspectra from a three-level atom.A.S. Jayarao, S.V. Lawanade and R. D'SouzaPhys. Rev. A42. 3044-30S0, (1990).
16. An Emission Spectrum of the InO* Molecular Ion.W.J. Balfour, M.D. SaksenaJ.M. Spectrosc., 143. 392 (1990).
3.2 §A?C_REPDRTS
1. Setting up and performance of a Laser Enhanced Ionizationspectrometer.L.C. Chandola, P.P. Khanna and M.A.N. RazviBARC Report - 1510.
2. X-ray Fluorescence Analysis of High Purity Rare EarthOxides for Common Trace Rare Earth Impurities.L.C. Chandola, R.M. Dixit, P.P. Khanna, S.S. Deshpand* and9.K. KapoorBARC Report - 1526 (1990).
1 6 J -
5.3 PAPERS PRESENTED IN CONFERENCES, SYMPOSIA, WORKSHOPS ETC.,I5
1. Laser production and detection of metal aaranol.A. Sharma2nd Annual Conference of Aerosol Society of India, BARC19-20 February, 199B.
2. Rovibrational Intensities of the Electric Quadrupole andMagnetic Dipole Transitions in Oxygen.T.K. Balasubramanian, R. D'Cunha, V.P. Bellary *ntiK.Narahari Rao45th Ohio State University Symposium on MolecularSpectroscopy, June 11-15, 1990.
3. High Resolution FT Spectroscopy of the 2uo Band of CD0CCH.K. Singh, G. Rajappan, V.A. Job, V.B. Kartha, A. Weber andW.B. Olsonibid.
4. High Resolution FTIR and Diode Laser Spectra of Propyne-din the 9-ll *m region.S.B. Kartha, V.A. Job, V.B. Kartha. A. Weber and W.B.Olsonibid.
5. Perturbations in the u7 state of CD.CCHR.J. Kshirsagar, CM. Medhekar, V.A. Job, V.B. Kartha,A.Weber and W.B. Olsonibid.
6. High Resolution Kpectroscopy studies of CHJFmu The v*band at 528.7 cm"M.N. Deo, R. D'Cunha, A.. Weber sad W.B. Olsonibid.
7. Interpretation of the High resolution Fourier transformspectrum of C^H, in the 2.4 im regionY.A. Sarma, R. D'Cunha, G. Guelachvili et alibid.
8. Integrated absorption coefficient of General xero-phonondouble transition of the type (AJ^l)^^ + S v*o
( a ) i n • o l i d
para hydrogenT.K. Balasubramanian, R. D'Souza, R. D'Cunha andK.Narahari Raoibid.
9. X-ray fluorsaconca spectrometer -for determination of tracerara earth olements in rarm earth materialsL.C. ChandolaProceedings of lecture course on Rare Earths held at RareEarths Division, Indian Rare Earths Ltd., Udyogmanda! ,April-May, 19B9.
IB. Inductiverly Coupled Plasma - Atomic Emission Spectroscopy(ICP-AEB) in Rare Earth AnalysisS.S. Biswasibid.
11. Two Photon Spectroscopy of autoionising levels of singletsulphur (3 So>T.V. Venkitachalam and A.S. RaoVIII National Workshop on At. and Mol. Physics, Dec.6-12,1990, Hyderabad.
12. (2+1) REMPI Spectroscopy of excited <3*Dt> sulphur ato*T.V. Venkitachalam and A.B. Raoibid.
13. Spectroscopic investigations on autoionising effects ofCulS. Padmanabhan, P. Meenakshi Raja Rao and C5. Krishnamurtyibid.
14. Temperature measurements in a laser ablation plasmaM.A.N. Razvi, G.L. Bhale, A. Sharma and V.B. Karthaibid.
15. Rotation-Vibration interaction in 2! electronic statesiTheory of Herman- Wai 1is correction factors torovibrational intensitiesOmana Harsy^n, T.K. Balasubramanian, V.P. Bellary andN.D. Patelibid.
16. Perturbations in the vibration-rotation hot bands of C^H,in the 2650 4100 cm regionY.O. Sarma and R. D'Cunhaibid.
17. lsotopir shift studies in levels of 4f35d*6s and 4f 5d6pconfiguration of Hm 11 and confirmation of some tentativeassignmpnts5.M. Af/al, S.G. Nakhate, Pushpa Rao, A. Venugopalan,S.A.rtrim iJ afiJ fi.D. fukspnai b i il .
1 8 . N o n l i m M r rpijimr? of saturated absorption line shape effect
C>f C C J I 1 1 SI (H)'.
H.K. Bhuwmik, B.N. Jagtap, S.A. Ahmad and V..B. Karthaibid.
L
19. Term shifts in odd and even parity lewis and theirvariation in -It n coupled status of 4f*S3d6»configuration of Yb*Pushpa M. Rao, S.A. Ahmad, G.D, Saksenaibid.
20. Multiphoton ionization of Ba«-iuin with tunable pulsed laserS.G. Nakhate, S.A. Ahmad, M.A.N. Razvi and G.D. Saksenaibid.
21. Laser excited two-photon Optogalvanic signals in NeonS.D. Sharma, K. Sunanda and G. Lakshminarayanaibid.
22. Laser Spectroscapy with metal aerosol particlesA. Sharma and S.S. De»shpandeInternational Workshop on Laser and Applications, 15-25Nov. 1990, Indore.
23. Fluorescence studies in the Multiphoton ionization ofbarium atomS.G. Nakhate, S.A. Ahmad, M.A.N. Razvi and G.D- Saksenaibid.
24. Measurement of decay times of the D2 level in Pr inYP04 and the studies of luminescence concentrationquenchi ngN.P. Karanjikar, M.A.N. Razvi and R.C. NaikSecond Indo-USSR Symposium on Rare Earth MaterialResearch, November 5-7, 1990, Trivandrun.
25. So Luminescence of Pr in LaFBK.H. Ayyar, M.J. Kamat and R C. Naikibid.
26. High resolution studies of the spectra of neutral »ndsingle ionised gadolinium for probing variation ofelectronic charge densityA. Venugopalan, S.A. Ahmad and 6.D. Saksenaibid.
27. Charge Radii and Shape transitions in shortlived Hg, Anand Pt. isotopesG. Passler, S. Becker, G. Bol1 en, M. Gaerber, T.Hilberath.H.J. Kluge, 0. Kronest and A. VenugopalanPresented at the Resonance Ionization Spectroscopy <RIS)Conference, Varese, Italy, 199B.
28. RIS of Technitium in a Laser Ion Source for a solarneutrino ExperimentF. Anas, H.J. Kluge, B.M. Suri, A. Venugapalan, H. Rieiee,N. Trautmann and R. KirchnerIbid.
n'f
29.
3B.
31,
32.
33.
34.
The 430 nm system of Indium OxideW.J. Balfour and M.D. SaksenaThe 72nd Canadian Chemical Conference,June 5-B, 19B9.
Victoria, Canada.
UV Spectra of InO and InO*W.J. Balfour and M.D. Saksena45th Symposium on Molecular Spectroscopy, Columbus, (Ohio,USA), June 11-15, 1990.
The Spectrum of InCl and InCl* RevisitedW.J. Balfour, K.6. Chandrasekhar and II.D. Saksena45th Symposium on Molecular Spectroscopy, Columbus, (Ohio,USA) June 11-15, 1990.
The B E*-x"£* transitionm of InO moleculeM.D. Saksena and W.J. Balfour8th National Workshop on Atomic and MolecularDecember 6-12, 1990, Hyderabad.
Physics,
5.4
Determination of Ce, Pr, Nd and Sm in high purity La^Q, byICP-AESS.S. Biswas, R. Kaimal, A. Sethumadhavan & P.S. MurtySecond INDO-USSR Symposium on Rare Earth MaterialsResearch organized by INSA and USSR Academy of Sciences,held at Trivandrum during Nov. 5-7, 1990.
Laser Excited Fluorescence of Hazardous PolycyclicAromatic Hydrocarbons Normally Found in Polluted AirR.Venkatasubramanian, M.N.Dixit and S.L.N.G.KrishnamachariNational Seminar on Radiation and Photochemical Processesof the Environment, Jan.17-19, 1990 organised by IndianSociety for Radiation & Photochemical Sciences (ISRAPS) atSaha Institute of Nuclear Physics, Calcutta.
INVITED TALKS
1. Spectroscopy and Radiometry with INDUS-1 - Proposals andpossibi1i ti esV.P. t'arthaVIIlth Nat. Sym. on Rad. Physics, (NSRP-8), Bombay,January, 1990.
2. Applied Laser Spectroscopy - Techniques and TrendsV.B. KarthaInd. Acad. Sciences, Mid-Year Meeting, July, 199B.
3. Laser Spectroscopy - A Kaledioscopic PictureV.B. KarthaAnn. Meeting, Ind. Nat. Science Academy* Indore, Aug.1990.
-IK-
4. Atomic: Molecular Spcctruwropy with L-arereV.B. KarthaDevi Ahilyabhui College, IndarR, Nov. 1990.
5. The Electric Quadrupnls and Magnetic DipolcrRotation-N/ibrHtion Spectrum of the Oxygen MoleculeT-K. BalaslubramanianDept. of Physical Chemistry., Justus-Liebig University o4Bicssen, Giessen, Germany, 7th August, 1990.
b. Probing nucltrir structure u'sing l*ser spectroscopyS.A. AhmadInternational Workshop on Lasers and Application*, 15-25Nov. 1990, CAT, Indore.
7. Laser Spectroscopy — An OverviewV.P. Karl haibid.
B. Laser Upuctroscopy in BARCV.B. Karthaibid.
9. Spectrascopy of Green Houee gases and other AtmosphericPollutantsR. D'CjniaNational Seminar on Radiation and Photochemical Proc«««e«of the Environment, Jan.17-19, 19^0, Saha Institute ofNuclaar Physics, Calcutta.
10. Spectrotcopic investigations of Atmospheric PollutantsR. D'CunhaEarth Day Craleberations' April, 1990, College of Williamand Mary, Hampton, Virginia, USA.
11. SpectroEcopic techniques for the study of green housegasesR. D'CunhaWorkshop on "Instrumentation in Research', Diamond JubileeCelebrations, Government of Maharashtra, I.Y. College ofArts and Science, Jogeshwari, Bombay, Dec. 4, 1998.
12. Beam -foil epectroscopyG. KrishnamurtyPhysics Colloquium Institute of Physics, Bhubaneahwar inJuly, 1990.
13. Photolonizatian and Optogalvanic Studias in Hollov-CatnodesS.D. SharmaNational Bymposium on Photoscianca, Dapt. of Physics,Kumaun University, Nainital, April 4-7, 1990.
6. OTHER ACADEMIC ACTIVITIES
£.1 Members registered for Ph.D degree
Name Guide Title of the research Degree
Shri. ^.P. Karanjikar
Shri. K. Harihara Ayyar
Shri. V.P. Bellary
Shri. B.J. Shetty
Smt. Pushpa M. Rao
Dr. S.L.N.G. Krishnamachari
Dr. N.A. Narashimham
Dr. S.L.N.G. Krishnamachari
Spectroscopic investigationsof some rare earth crystals.
Spectroscopic investigationsof some rare earth complexes.
Spectroscopic investigationsof some theoretical aspectsin diatomic molecules.
Dr. S.L.N.G. Krishnamachari Spectra of diatomic molecules
Dr. G.D. Saksena Isotope shifts and hyperfinestructure in rare earth atoms,
Ph.D.Phy3ics
Ph.D.Physics
Ph.D.Physics
Ph.D.Physics
Ph.D.
Shri. G.K. Bhowmick
Shri. P.P. Khanna
Kum. Charusheela M.Medhekar
Shri. R.J. Kshirsagar
Dr. V.B. Kartha
Dr. G.D. Saksena
Dr. G.D. Saksena
Dr. V.B. Kartha
(Title to be given) Ph.D.Chemistry
Laser enhanced ionisation Ph.D.spectrometry Physics
High resolution spectroscopy Ph.D.of polyatomic molecules. Physics
High resolution diode laser Ph.D.and Fourier Transform Spect- Chemistryroscopy of simple polyatomicmolecules.
Name Guide Title of the research Degree
Shri. M.A.N. Razvi
Smt. S.S. Deshpande
Shri. M.N. Deo
Kum. Savita Narang
Smt. Geetha Rajappan
Smt. Omana Narayanan
Smt. S. Venkateswaran
Dr. P.R.K. Rao
Dr. G.D. Saksena
Dr. V.B. Kartha
Dr. G.D. Saksena
Dr. V.B. Kartha
Dr. G.D. Saksena
Dr. V.B. Kartha
(Title to be given)
(Title to be given)
(Title to be given)
Infrared, Raman and Photo-acoustic studies of solidsand crystalline materials.
(Title to be given)
(Title to be given)
(Title to be given)
Ph.D.Physics
Ph.D.Physics
Ph.D.Chemistry
Ph.D.Physics
Ph.D.Chem.
Ph.D.Phys.
Ph.D.Chem.
- J 9 6 -
SPECTROSCOPY DIVISIONBHABHA ATOMIC RESEARCH CENTRE
Dr. V.B. Kartha, Head
SPECTROCHEMICAL ANALYSIS, DEVELOPMENT OF ANALYTICAL METHODS AND BASIC RESEAP^H IV. SPECTROSCOPE
Dr. A.V.Sankaran(Section Head)Dr.Dr.ShriShriShrlShriShriSmt.Smt.Smt.Smt.Srat.Shri
P.SreeramamurtyL.C.Char.dcla. S.S.Biswas**. S.M.Marathe**. I.J Machado**. A.Sethumadhavan*». P.P.Khanna»*S.S.Deshpande**V.S Dixit**Geetha Rajappan**Omana Narayanan**F.B.Patil**
.. B.K.Ankush**
Phys.Geol.frhys.PhysChem.Phys.Chen.Phys.Phys.Phys.Chem.Chem.Phys.Phys.Chem.
SG
SGSFSESESDSDSDSCSCSACSACSACSAC
(I) Analytical Spectroscopy
10.11.12.13.14.
Trace end ultra-trace analysis of reactormaterials and mia^eilear.ous sas&pXco tyectsalon apectroscopy.
(IV) Atomic Spectra and Optics
29. Dr. G.D.Saksena Phys. G(Section Head)Atomic Spectra-
30. Dr. S.A.Ahmad Fhys. SG31. Dr. R.C.Nalk Phys. SF32. Shri. N.P.KaranJikar Fhys. SF33. Shri. K.Harihara Ayyar** Phys. SE34. Dr. A.Venugopalan** Phys. SD35. Sst. Pushpa M. Rao Phys. SD36. Shri. S.G.Nakhate Phys. C37. Shri. S.K. Kapoor** Phys. SC
Isotope shift studies of rare earths.Application of laser spectral studies toaccelerator produced isotopes. Low temp-erature fluorescence & absorption spectraof rare e*rth Ions doped In crystallineMatrices.
(II) X-ray Spectrosccpy
15. Shri. R.M.Agrawal Chem. SF16. Shri. H.J.Kaaat** Phys. SE17. Shri. S.N.Jha Chem.' C18. Smt. Rugmini Kaimal** Chem. SC19. Shri.S.K. Malhotra** Chea. SE
Development of methods of x-ray fluores-cence and x-ray excited optical lumir.i-icenie' analysis of rare earths endother impurities in reactor materials.
Optics:
38. Dr.K.V S.R.Appnrao Phys SF39. Dr.N.C. Das (Optics) Phys. £F40. Dr.R.P. Shukla » (Optics) Phys. SE41. Shrl.T.K.Kunchur Phys. SC42. Shri.S.S.Bhattacharya Mech.D roan oC43. Shri.T.C.Bagchi(Electronics)Phys. SB44. Shri. B.S. Deshpande
Glass Blowing T'nan H
Design and fabrication, of high precisionoptical components, instr'iments and thinfilm multi-layer coatings for spectro-scopic and laser applications.
(Ill) Infrared, Raman and PAS
20. Dr. V.A.Job Chen.. SG(Section. Head)
21. Dr.(Smt) R.D'Cunha Chen. SU22. Dr. N.D. Patel Chea. SF23. Dr. Y.A. Sarma Phys. SE24. Dr.(Smt) Shantha Kartha Phys. SE25. Dr. Kuldip Singh Chem. SE26. Shri. R J. Kshirsagar Chera. SD27. Snri. M.N. Deo Chen.. SC28. Smt. S.Venkateswaran** Chea. SB
Kua. C.M.Medhekar +Kum. S.N.Narang +
Infrared and Raman studies of organic andi r.r rgar. i - materials- Hxgh resolution in-frared studies of polyatomic rroleculfs.FhotcaccusTlc spfctrosccpy studies cfsolids.
(V) Molecular Electronic Spectra
45. Dr.T.K.Bslasubramf.niar.(Section Head)
46. Dr.4 7 . Dr. Mahav i r S i n g h<r. E h r i . V . P . Bel iar . . .4V r>r.G S. Ghodg&onkar5'^ Or.(Kum) S h e i l a Gi.pal5 1 . Dr. B. Venkat .asubremani .an**5 2 . S a t . Sunanda K. Kumar53. Dr. M.D. Saksena**54. Shri. B.J. Shetty**
High resolution studies of the electronicspectra of diatomic and simple polyatomiccolecules:electronic 6pectrs of transientspecies. Theoretical studies on highresolution 3p«ctra.
Phys.
Khys.Phv-3.
Ph! S.Fhys.Chen.Fhys.Phys.Phys.
PG
SFSFSF3ECEsr>c
SCSC
: 2 :
(VI) Laser Spectroscopy (VII)
55.
56.5?.58.59.60.il.62.63.
Dr. M.N.(SectionDr. G.L.Dr. S.D.Dr. T.V.Dr. R.D'
DixitHead)BhaleShannaVenkitachalam
SouzaDr. Anup ShannaShri A.£Shri. MShrl. P
suryaprakasa Rao**.A.N. Razvi.K.Krishnan Unni
Glass
Fhys.
Fhys.Phys.Fr.ys.Fhys.Phys.Phys.Fhys.
Blowing
5G
SFSFSESESESDSD
SC
65.66.67.68.69.70.
Beam Foil, PlaSpectroscopy
Dr. G. KrishnamurtyDr.(Smt) P.M.Raja RaoShri. S. V.N. Bhaskara itaoDr.(Smt) S.Fad.T.an£bhan**Shri. A. P. P.ishraShri. B.N.Rsja Sekhar
nchro
Phys.Phys.Phys.Phys.Phys.Phys.
tron
SFSESDSDCSC
(VIII)
71.72.73.74.75.76.
ShriShriSrat.ShriShriShri
Electronics
. F.K.S.Prakasa Rao (Electronics)
. S.V.G.Ravindranath(Electronics)Manika Das. K.N. Patil. H.C. Patil. Rajiv Slnha
(Electronics)(E.ectronics)(E-ectror.ics)(Electronics)
SFSEC
SBSADSAC
64. Shri. M.B. Guhagarkar Mech D'man SC
Development of lasers for spectroscoplcstudies: Development of new laser systemsthrough spectroscopic investigations.Development of laser based instruments &analytical methods. Theoretical studiesof interaction of laser radiation withnatter.
Study of spectra of high.'.y ionized atomsusing Beam Foil techniques: Instrument-ation for synchrotron radiation spectro-scopy: Plasma spectroscopy.
Maintenance of the electronic units: designand development of electronic units forspectroscopic and laser activities: Computerbased instrumentation.
+ Bombay UniversityResearch
• On EOL abroad
* Also Involved in
JuniorFellow
Service
Scientific
GSGSFSESD
: 2: 7: 15: 14•• 11
Analysis
and Technical
SO(C) :SC :SB :SAD :SAC =
512415
Supporting Staff
T'ma.-i (H)T'mari (G)F.M.(A)T'man (F)T'man (E)T'man (D)fman (B)T ' M * (A)
11145311
Administrative Staff
A.O. IIStenographer (Grade II)Stenographer (Grade III)Dpper Division ClerkLower Division Clerk
: 1: 1: 2: 1; 1
Auxiliary
Helper (C&M) : 2
Number of persons working outside Trombay C ScientificC TechnicalC Administrative iftllC Auxiliary • . . . . . . . .
Published by : M. R. Balakrishnan Head, Library & Information Services DivisionBhabha Atomic Research Centre Bombay 400 085
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