Volume 74A, number 1,2 PHYSICSLETTERS 29 October1979

DOUBLE-PLASMON HIGH-ENERGY SATELLITEIN THE K X-RAY EMISSION SPECTRA OF MAGNESIUM

S.P.SINGHDepartmentof Physics,K.N. Govt.PostgraduateCollege,Gyanpur, Varanasi, UP., India

Received15 February1979Revisedmanuscriptreceived21 August 1979

Thea~, a6 anda10 high-energysatellitesin theK X-ray emissionspectraof Mg arethesingle-,double-andtriple-plasmonhigh-energysatellites,respectively.Othersatellitesmaybedueto a different combinationof surfaceplasmons(hw

5 =

andvolume plasmons(Wp = 4irne2/m). Therelativeintensity of thea

6satellite with respectto Kai,2 hasbeencalculatedas0.42%usingLangreth’sformalism,which is in goodagreementwith thevalueobservedby KrauseandFerreira.

Single-anddouble-plasmonhigh-energysatellitesap- (seetable 1). It is also our aim to calculatetherelativepear in X-ray emissionspectradue to enhancedde-exci- intensityof thea6 satelliteandcomparethe resultwithtationenergyowing to theabsorptionof singleaswell the observedvalue.asdoubleplasmons(k~,, 2hw~)by thevalenceelec- The energyseparation10.1 eVcorrespondswell withtron undertransition.The earliermentionedsatellite theCEEL value10.5 eV [11] andthe plasmonenergyhasbeenreportedby severalworkers[1—4].Srivastava 10.2 eV [6,12]. Thereforethea4 satellitein theK X-rayet al. [5,6] andSingh [7] havealreadydiscussedthe emissionspectraof Mg maybe a single-plasmonhigh-K~satelliteof magnesium[8] and the Augersatelliteof energysatellite.A glanceat table 1 showsthat thea6B~respectivelyassingle-plasmonhigh-energysatellites, satellite is a double-plasmonhigh-energysatelliteIn 1975,KrauseandFerreira[9] haveobservedthea4, (DPHES).To confirm this assignmentthe authorhasa5,a6,a8,a10,a11 anda14high-energysatellitesat en- further calculatedthe relativeintensityof the a6 satel-ergyseparations10.1 eV, 17.4eV,20.6eV, 15.7eV, lite. Following Langreth[13] therelativeintensity(re-30.0eV, 27.1 eV and37.7eV fromKal,2with relative lative strength)of thedouble-plasmonsatellitecanbeintensities5.1%,0.76%,0.48%,0.12%,0.06%,0.03%and givenby0.01%,respectively.KrauseandFerreirahavealso re- — ~ 06 X ~2\/2 —~ “1portedvarioussatellitesin the X-ra~remissionspectraof —‘ ~ ~ eAl andAl203, which are analogousto the satellitesof where13 is e

2kcllrhwp which canbeapproximatedasMg. Thesesatelliteshavebeendiscussedby the author 0.12r

5 [14]. Formagnesiumthe inter-electronicspac-somewhereelse.Accordingto KrauseandFerreira[91, ingin Bohr radii is 2.6556 [15]. Substitutingthevaluethea4 line arisesfrom an initial KL defect,thea5,a6 of 13 (j3 = 0.32)in eq.(1), therelativestrengthcomesand a8 lines from KL

2 defects,andthea10and a11 outto be 0.42%whichagreeswell with therelativein-

lines from KL3 defects.The abovesatellitescanequally tensity0.48%observedby KrauseandFerreira[9].

well beexplainedon thebasisof theplasmonenergy The abovecomparisonclearly indicatesthat thea6

gain process[10] aboutwhich nothinghasbeensaidso satelliteof Mg canbe attributedto DPHES. In addition,far. Thereforeit is thoughtof greatinterestto compare a10maybe a triple-plasmonhigh-energysatelliteandthe relativeenergiesof thesatellitewith characteristic all othersatellitesin table 1 maybe due to theplasmonelectronenergylosses(CEEL)and plasmonenergies energygain process.

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Volume 74A, number1,2 PHYSICSLETTERS 29 October1979

Table 1

Satellites ~E(Obs.) [91 CEELvalue [11] Plasmon Assignment(eV) (eV) energy

(eV)

a4 10.1 10.5 10.2 11w

a5 17.4 17.0 17.5 11w~+hw5a6 20.6 21.0 20.4 2hwa8 15.7 15.0 14.6 2Bw~

30.0 — 30.6 311wa11 27.1 27.7 2flw~+11w5a14 37.7 — 37.9 3hw +hw5

Theauthoris gratefulto Dr. K.S.Srivastava,Lucknow [61K.S. Srivastava,S.P.Singhand R.L. Shrivastava,Phys.

University for helpful discussionsandsuggestions,and Lett. 47A (1974)305.[7] S.P.Singh,Indian J. PureAppl. Phys. 16 (1978)715.to Dr. S.S. Khanna(Principal)for encouragement.Fi- [8] V. Kunzl, Z. Phys.99 (1936)481.

nancialassistancefrom the University GrantsCommis- [9] M.O. KrauseandJ.G.Ferreira,J. Phys.B8 (1975)2007.

sion,NewDelhi, is acknowledged. 1101 V.V. Shmidt,Soy. Phys.JETP 12 (1961) 886.

[11] L.H. JenkinsandM.F. Chung,Surf. Sci. 33 (1972) 159.References [12] B. FeuerbacherandB. Filton, Phys.Rev. Lett. 24 (1970)

499.[13] D.C. Langreth,Initial collectivepropertiesof physical

[1] W.F. HansonandE.T. Arakawa,Z. Phys.251 (1972) 271. systems,Nobel Symp.24 (1973)p. 210.[2] L H. JenkinsandD. M. Zehner,Solid StateCommun. 12 [14] K. S. Srivastava,S.P.Singhand R.L. Shrivastava,Phys.

(1973) 1149. Rev. B13 (1976) 3213.[3] L.H. JenkinsandM.F. Chung, Surf.Sci. 28 (1971)409. [15] G.A. Rooke,in: Soft X-ray bandspectraandtheelec-[4] M.F. Chungand L.H. Jenkins, Surf.Sci. 26 (1971) 649. tronic structureof metalsandmaterials,ed.D.J. Fabian[5] K.S. Srivastava,R.L. Shrivastavaand S.P.Singh, Indian (Academic,New York, 1968)p. 8, table 1.

J. PureAppl. Phys.14 (1976) 134.

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