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Trends in heavy ion sciences 24 May, 2008
Trends in heavy ion sciences 24 May, 2008
Why experimenters like to come to Dubna: Scientific success is always a good reason to organize a big party!
Trends in heavy ion sciences 24 May, 2008
How chemists have reached the island of spherical superheavy elements
Heinz W. GäggelerPaul Scherrer Institut and
Bern University, Switzerland
Laboratory for Radiochemistry and Environmental Chemistry
Chemistry of volatile 7p-elements = chemistry of spherical SHE
Recent studies with IVO: In-Situ volatilisation and On- line detection (developed for first chemical study of hassium but recently applied for element 112 and 114)
Are relativistic effects influencing the chemical property of element 114?
sea of instability
sea of instability
island of Superheavy
Elements
Number of neutrons
Nu
mb
er
of
pro
ton
s
20
50
82
114
20 82 126 184
peak of Sn
peak of Ca
peak of Pb
peak of U
strait of radioactivity
strait of insta- bility
G.N. Flerov, A.S. Ilyinov (1982)
Trends in heavy ion research, 24 May 2008
Shell stabilisation
Courtesy: S. Hofmann
deformed
spherical
PeriodicPeriodicTable of Table of thethe Elements
DsDs
H
Li
Na
K
Rb
Cs
Fr Ra Ac
Ba
Sr
Ca
Mg
Be
Sc
Y
La
Ti
Zr
Hf
V
Nb
Ta
Cr
Mo
W
Mn
Tc
Re
Fe
Ru
Os
Co Ni Cu Zn Ga Ge As
Rh Pd Ag Cd In Sn Sb
Ir Pt Au Hg Tl Pb Bi
Rf Db Sg
B C N O F
Al Si P S Cl
Se Br
Te I
Po At87 88 89 104 105 106
55 56 57 72 73 74 75 76 77
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
78 79 80 81 82 83 84 85
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
11 12 13 14 15 16 17
3 4
1
5 6 7 8 9
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
58
90
59 60 61 62
91 92 93 94
63
95 96 97 98 99 100 101
64 65 66 67 68 69
102 103
70 71
LanthanidesLanthanides
ActinidesActinides
Bh107
Hs
Mt
108
109 110
RgRg111
112
114 116
- -
He
Ne
Ar
Kr
Xe
Rn
54
86
36
18
10
2
18
113113
114
115115
116116
118118
Mendelejev‘s first Periodic Table Mendelejev‘s first Periodic Table from 1871from 1871
Basis for the discovery of several new elements!
H
Li
Na
K
Rb
Cs
Fr Ra Ac
Ba
Sr
Ca
Mg
Be
Sc
Y
La
Ti
Zr
Hf
V
Nb
Ta
Cr
Mo
W
Mn
Tc
Re
Fe
Ru
Os
Co Ni Cu Zn Ga Ge As
Rh Pd Ag Cd In Sn Sb
Ir Pt Au Hg Tl Pb Bi
Rf Db
B C N O F
Al Si P S Cl
Se Br
Te I
Po At87 88 89-103 104 105
55 56 57-71 72 73 74 75 76 77
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
78 79 80 81 82 83 84 85
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
11 12 13 14 15 16 17
3 4
1
5 6 7 8 9
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
LanthanideLanthanidess
AAcctinidetinidess
114
- -116
- -
He
Ne
Ar
Kr
Xe
Rn
54
86
36
18
10
2
18
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
58
90
59 60 61 62
91 92 93 94
63
95 96 97 98 99 100 101
64 65 66 67 68 69
102 103
70 71
La
Ac
57
89
Positioning of new elementsPositioning of new elementsinto the Periodic into the Periodic ttableable
Sg106
Bh107
Hs108
Mt109 110
Ds Rg112
- -
Sg106
20002000
Bh107
Hs108
200220022001 - 20072001 - 20071993 - 19971993 - 1997
112
- -114
- -
≥ 2007
111 113 115 116 118
Trends in heavy ion research, 24 May 2008
Reactions used and number of atoms found in the „first ever chemical studies“ in the last decade
Bohrium (Z=107); Main experiment at PSI249Bk(22Ne;4n)267Bh (T1/2 = 17 s); 6 atoms (R. Eichler et al., Nature, 407, 64 (2000))
Hassium (Z=108); Main experiment at GSI248Cm(26Mg;5n)269Hs(T1/2 = 15 s); 7 atoms (C.E. Düllmann et al., Nature, 418, 860 (2002))
Element 112; Main experiment at FLNR/JINR242Pu(48Ca,3n)287114 (T1/2 = 0.5 s)283112 (T1/2 = 4 s); 2 atoms (R. Eichler, Nature, 447, 72,2007); meanwhile 5 atoms in total (R. Eichler et al., Angew. Chem. Int. Ed., 47,1(2008))
Element 114: Main experiment at FLNR/JINR; ongoing. Currently evidence for 3 - 5 atoms
IIsothermsothermalal CChromatographhromatography: Sg,Bhy: Sg,Bh
Tem
per
atu
re [
°C]
Column length [cm] Temperature [°C]
Yie
ld [
%]
50%TtRet. = T1/2
Gas flow
highlow
TThermochromatographhermochromatography: Hs, Z=112; Z=114y: Hs, Z=112; Z=114
Tem
per
atu
re [
°C]
Column length [cm] Temperature [°C]
Yie
ld [
%]
Ta
high
Gas flow
low
Elements with Z ≥ 112: filled 6d10 shell: 7p-element behaviour (volatile noble metals)
DsDs
H
Li
Na
K
Rb
Cs
Fr Ra Ac
Ba
Sr
Ca
Mg
Be
Sc
Y
La
Ti
Zr
Hf
V
Nb
Ta
Cr
Mo
W
Mn
Tc
Re
Fe
Ru
Os
Co Ni Cu Zn Ga Ge As
Rh Pd Ag Cd In Sn Sb
Ir Pt Au Hg Tl Pb Bi
Rf Db Sg
B C N O F
Al Si P S Cl
Se Br
Te I
Po At87 88 89 104 105 106
55 56 57 72 73 74 75 76 77
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
78 79 80 81 82 83 84 85
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
11 12 13 14 15 16 17
3 4
1
5 6 7 8 9
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
58
90
59 60 61 62
91 92 93 94
63
95 96 97 98 99 100 101
64 65 66 67 68 69
102 103
70 71
LanthanidesLanthanides
ActinidesActinides
Bh107
Hs
Mt
108
109 110
RgRg111
112
114 116
- -
He
Ne
Ar
Kr
Xe
Rn
54
86
36
18
10
2
18
113113
114
115115
116116
118118
How to experimentally determine a metallic character of a volatile element at a single
atom level?
→ Determine interaction energy (adsorption enthalpy) with noble metals (e.g. Au)
→ If metallic: strong interaction (adsorption enthalpy) if non-metallic (noble gas like): weak interaction
Adsorption of single atoms of mercury and radon on a gold
surface
0
5
10
15
20
25
30
35
40
45
50
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
lenght [cm]
yiel
d [
%]
0
50
100
150
200
250
300
350
400
450
500
tem
per
atu
re [
K]
192Hg Hads = -87 kJ/mol219Rn Hads = -27 kJ/mol
Adsorption of single atoms of mercury and radon on a quartz surface
0
10
20
30
40
50
60
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32lenght [cm]
yiel
d [
%]
0
50
100
150
200
250
300
350
400
450
500
tem
per
atu
re [
K]
192Hg Hads = -24.5 kJ/mol219Rn Hads = -20.5 kJ/mol
Trends in heavy ion science, 24 May 2008
Correlation between adsorption properties of single atoms on gold Correlation between adsorption properties of single atoms on gold
and their macroscopic sublimation enthalpyand their macroscopic sublimation enthalpy
Texas A&M, Nov. 2007
DsDs
H
Li
Na
K
Rb
Cs
Fr Ra Ac
Ba
Sr
Ca
Mg
Be
Sc
Y
La
Ti
Zr
Hf
V
Nb
Ta
Cr
Mo
W
Mn
Tc
Re
Fe
Ru
Os
Co Ni Cu Zn Ga Ge As
Rh Pd Ag Cd In Sn Sb
Ir Pt Au Hg Tl Pb Bi
Rf Db Sg
B C N O F
Al Si P S Cl
Se Br
Te I
Po At87 88 89 104 105 106
55 56 57 72 73 74 75 76 77
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
78 79 80 81 82 83 84 85
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
11 12 13 14 15 16 17
3 4
1
5 6 7 8 9
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
58
90
59 60 61 62
91 92 93 94
63
95 96 97 98 99 100 101
64 65 66 67 68 69
102 103
70 71
LanthanidesLanthanides
ActinidesActinides
Bh107
Hs
Mt
108
109 110
RgRg111
112
114 116
- -
He
Ne
Ar
Kr
Xe
Rn
54
86
36
18
10
2
18
113113
114
115115
116116
118118
Element 112 similar to Hg?
Window/Target (242Pu: 1.4 mg/cm2)
Beam (48Ca; 233-239 MeV)
Beam stop
SiO2-FilterTa metal850°C
Quartz column
Cryo On-line Detector (4Cryo On-line Detector (4 COLD)COLD)
Carrier gas He/Ar (70/30)
Teflon capillary
(32 pairs PIN diodes, one side gold covered)
HgHg Loop
Temperature gradient: 35°C to – 184 °C
T
l
RnRn
The element 112 experimentThe element 112 experiment(IVO (IVO [I[In-situ n-situ VVolatilisation andolatilisation and O On-line detectionn-line detection]]
Technique)Technique)
111122Recoil
chamber
Quartz inlay
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
Studies on element 112Studies on element 112 242242Pu(Pu(4848Ca;3n)Ca;3n)287287114 (0.5 s) 114 (0.5 s) → 4s → 4s 283283112112 Reasons Reasons
a) High cross section of a) High cross section of 5 pb ( 5 pb ( 3-times higher than 3-times higher than via direct production with via direct production with 238238U as a target)U as a target)
b) Residence time in collection chamber and transport b) Residence time in collection chamber and transport capillary capillary 2 s 2 s 283112
9.54 MeV
4 s
Rf 2614 s
8.5 MeV
Ds 279
0.2 s
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
10
50
0.1
0.5
Cro
ss s
ecti
on
s / 3
MeV
(re
lati
ve u
nit
s)
1
5
3n2n
3n
2n
4n5n
4n
5n
30 3525Excitation energy (MeV)
40 45 50 55
xn-channel cross sectionsfrom 242,244Pu+48Ca reactions
Excitation functionsExcitation functions
Courtesy: Yu. Oganessian. “Heaviest Nuclei from 48Ca-induced Reactions” TAN-07, Davos, Sept. 23-27, 2007
283112
9.37 MeV
287114
279Ds: 0.592 s
SF108+123 MeV
Observed in Chemistry:Observed in Chemistry:11.05.20062:40 (moscow time)
283112
9.48 MeV
287114
279Ds: 0.536 s
SF127+105 MeV
25.05.20068:37 (moscow time)
Result from the Result from the 4848Ca + Ca + 242242Pu experimentPu experiment
Laboratory for Radiochemistry and Environmental Chemistry
Three week bombardment with 3.1x1018 48Ca ions at 236 ± 3 MeV
First independent confirmation of 283112 formation and decay properties! (R. Eichler et al., Nature, 447, 72 (2007))
283112
9.35 MeV
287114
279Ds: 0.773 s
SF85+12 MeV
Result from additional Result from additional 4848Ca + Ca + 242242Pu experiments in Pu experiments in 20072007
Bombardment 21.3.- 17.4. 2007 with 3.1x1018 48Ca ions at 237± 3 MeV
283112
9.52 MeV
287114
279Ds: 0.072 s
SF112 + n.d MeV
283112
9.52 MeV
287114
279Ds: 0.088 s
SF94+51 MeV
The chemistry experiment is not sensitive to the 4n channel (too short-lived nuclides)
The chemistry of element 112The chemistry of element 112
Element 112 is similar to Hg, but slightly more volatile
Deduced adsorption enthalpy: -52-52+20+20-4-4 kJ/mol (black solid line) kJ/mol (black solid line)
Trends in heavy ion science, 24 May 2008
The chemistry of element 112The chemistry of element 112
HHsublsubl=39=39+23+23-10 -10 kJ/mol (68% c.i.)kJ/mol (68% c.i.)
-52-52+20+20-4-4 kJ/mol kJ/mol
Trends in heavy ion science, 24 May 2008
Trend of sublimation enthalpy within group 12Trend of sublimation enthalpy within group 12
Trends in heavy ion science, 24 May 2008
What‘s next?
• Search for relativistic effects in the chemistry of element 114 (group 14 with [Rn]7s26d107p2)
• Relativistic effect: influence of increasing Coulomb attraction between atomic electrons and nucleus
from: V. Pershina et al., J. Chem. Phys., 127, 134310 (2007)
Group 14:
6d107s27p2
Prediction by Pitzer (1975)
Is element 114 a noble gas due to a strong spin-orbit splitting of the 7p orbitals?
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
Studies on element 114Studies on element 114 Reaction: Reaction: 242242Pu(Pu(4848Ca;3n)Ca;3n)287287114 (T114 (T1/21/2 =0.5s) =0.5s)
(FLNR; spring 2007)(FLNR; spring 2007)
Rf 2614 s
8.5 MeV
Ds 279
0.24s
283112
287114
10.9 s
9.54 MeV
10.0 MeV1 atom on Au at – 80 °C
3.1x1018 48Ca ions at 237± 3 MeV
unpublished
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
Studies on element 114Studies on element 114 Reaction: Reaction: 244244Pu(Pu(4848Ca;4n)Ca;4n)288288114 (T114 (T1/21/2 =0.8s) =0.8s)
Rf 2614 s
8.5 MeV
2 atoms on Au at –10 °C & -84 °C
Beam dose 4x10Beam dose 4x101818
Energy within targets: Energy within targets: 243 – 231 MeV243 – 231 MeV((~ 1.4 mg/cm~ 1.4 mg/cm22))
288114 288114
9.95 MeV 9.81 MeV
284112 284112
0.11 s 0.11 s
unpublished
Current experiment lasting until 8 June 2008 at FLNR:48Ca + 244Puto produce0.8 s 288114 (4n-channel)2.7 s 289114 (3n-channel)
Chemistry behind the Dubna gas-filled separator
Pro & Contra
• Pro:- Extremely clean - spectra (no background)- no sf-contamination by sputtered target
• Contra:- Lower efficiency- Smaller energy range in the thin target
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
Studies on element 114Studies on element 114
Reaction: Reaction: 244244Pu(Pu(4848Ca;3n)Ca;3n)289289114 (T114 (T1/21/2 =2.7s) (FLNR; =2.7s) (FLNR; ongoingongoing 2008) 2008)
Rf 2614 s
8.5 MeV
281Ds
3.3s
285112
289114
9.12 MeV
Not detected
1 atom on Au at – 97 °C
4x1018 48Ca ions at E* = 38 – 42 MeV
SF 106+50
unpublished
-200
-150
-100
-50
0
50
-200
-150
-100
-50
0
50
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 320
2
4
6
8
10
Hads
Au=-35 kJ/mol
288114
Detector #
icegold
0
2
4
6
8
10 ice
Pu-244
Rel
. yi
eld
/ de
tect
or,
%Pu-242 gold
Tem
per
atur
e, °
C
287114
Hads
Au=-35 kJ/mol
Decay during transport?
Prelim
inary
unpublished
0 50 100 150 200 2500
50
100
150
200
250 experimantal data least square fit: 95% c.i.
-Hads
(Au) = (1.08±0.05)*Hsubl
+(10.3±6.4), kJ/mol
-H
ads(A
u), k
J/m
ol
Hsubl
, kJ/mol
At
Hg
RnXe
Kr
Tl
Bi
PbPo
E114
Prelim
inary
Result from the chemistry experiment with element 114
→ Element 114 exhibits a very weak adsorption on Au, pointing to van der Waals interaction (similar to a noble gas).
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
ConclusionConclusion Chemical research on heaviest elements has Chemical research on heaviest elements has
been much boosted by the recent discoveries of been much boosted by the recent discoveries of many new nuclides up to Z=118 at FLNR many new nuclides up to Z=118 at FLNR
Chemical studies at the few atom level have Chemical studies at the few atom level have been sucessfully conducted up to Z = 112 been sucessfully conducted up to Z = 112
Elements Bh, Hs & 112 (as well as Rf, Db, Sg) Elements Bh, Hs & 112 (as well as Rf, Db, Sg) behave in gas phase studies as expected from behave in gas phase studies as expected from extrapolations within the groups of the periodic extrapolations within the groups of the periodic tabletable
Ongoing studies point to an element 114 Ongoing studies point to an element 114 behaviour unlike that of eka-Pb, but rather behaviour unlike that of eka-Pb, but rather similar to a noble gas. similar to a noble gas.
Trends in heavy ion science, 24 May 2008Trends in heavy ion science, 24 May 2008
Many thanksMany thanks
To Yuri Oganessian for his constant To Yuri Oganessian for his constant support and very active engagement support and very active engagement in the experimentsin the experiments
To Sergei Dmitriev and his team for To Sergei Dmitriev and his team for the Dubna chemiststhe Dubna chemists
To Georgi Gulbekian and his team for To Georgi Gulbekian and his team for the excellent the excellent 4848Ca beamsCa beams
To Robert Eichler and his team from To Robert Eichler and his team from the PSI/Univ. Bern collaborationthe PSI/Univ. Bern collaboration
Raw data from few-hour measurement with pre-separation (GNS) (left) and without (right)
219Rn 215Po
212Po214Po211At