Transcript Folie 1

Laboratory for Radiochemistry and Environmental Chemistry
Mendeleev’s principle against Einsteins relativity
news from the chemistry of superheavy elements
H.W. Gäggeler
>
Reminiscences: from Mendelejeev’s periodic table to the
discovery of mendelevium, the last “real” chemical element
>
Positioning four new chemical elements into the periodic table
during the last decade. Mendelejeevs dreams become true!
>
How reliable is single atom chemistry? Proof of principle with
elements Hs and 112
>
Einsteins influence on the chemistry of heaviest elemenst, so far
up to Z=114
Mendeleev; Dubna 2009
Mendelejeev‘s „second“ Periodic
Table from 1871
D.I. Mendeleev (8 Feb. 1834 – 2 Feb. 1907)
Predictions by Mendeleev in 1871



Eka-Al: Discovered by P.E. Lecoq de
Boisbaudran in 1875, named Ga
Eka-B: Discovered by L.F. Nilson in
1879, named Sc
Eka-Si: Discovered by C. Winkler in
18886, named Ge
Major refinements



Noble gases: Sir William Ramsey
(1894)
Henry Moseley: Atomic number,
determined via X-rays, defines
ordering of elements (1914)
Glenn T. Seaborg: Actinides series
(1945)
Periodic Table in the 1930‘s
G.T. Seaborg, W. D. Loveland (1990)
Periodic Table today
1
18
1
2
H
2
13
14
15
16
17
He
3
4
5
6
7
8
9
10
Li
Be
B
C
N
O
F
Ne
11
12
13
14
15
16
17
18
Na Mg 3
4
5
6
7
8
9
10
11
12
Al
Si
P
S
Cl
Ar
19
20
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
K
Ca Sc
Ti
V
Cr
Mn Fe
Co Ni
Cu Zn
Ga Ge As
Se
Br
Kr
37
38
39
40
41
42
43
45
47
48
49
50
51
52
53
54
Rb Sr
Y
Zr
Nb Mo Tc
Ru Rh Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
55
56
57-71
72
73
74
75
76
78
79
80
81
82
83
84
85
86
Cs
Ba
La
Hf
Ta
W
Re Os Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
87
88
89-103
104
105
106
107
115
116
116
Fr
21
Ra Ac
57
58
59
Lanthanides La Ce Pr
Actinides
60
46
77
112
108
61
114
--
Bh Hs
Db Sg
Rf
44
62
109
110
Mt
Ds Rg
63
111
64
114
113
65
66
67
68
69
118
70
71
Nd Pm Sm Eu
Gd Tb
Dy
Ho Er
Tm Yb
Lu
96
98
99
100
101
103
Cf
Es
Fm Md No Lr
89
90
91
92
93
94
95
97
Ac
Th
Pa
U
Np Pu Am Cm Bk
102
LogT1/2
(sec)
CHART OF THE NUCLIDES
130
Superheavy
Elemens
120
Proton number
110
14
Transuranium
Elemens
100
298
114
90
Spherical
Shell
Stable
Elemens
80
10
70
208
60
Spherical
Shell
6
Pb
50
2
40
Sea of Instability
30
-2
20
10
-6
0
10
20
30 40 50
60
70
80
90 100 110 120 130 140 150 160 170 180 190 200
Neutron number
Courtesy: Yu.Ts. Oganessian
Discovery of new elements – the failure of chemistry!
The heaviest element discovered purely by chemical
means: Mendelevium! (1955)
→ Synthesis: bombardment of 253Es with a-particles.
→ Collection of products in a foil.
→ Separation of products after dissolution of foil on a cation
exchange column with a-HIB
Mendeleev, Dubna 2009
Count rate [cpm]
Elution of actinides on a cation exchange
column by a-HIB
Elution in drops
Discovery of Mendelevium on the basis of 7 atoms
unknown
Es
Cf
Fm
A. Ghiorso et al., Phys. Rev. 98, 1518 (1955)
Mendeleev, Dubna 2009
Positioning of new elements
during the last decade
1
18
1
2
H
2
3
4
Li
Be
11
12
2009?
2002
2007
1999
13
14
15
16
17
He
5
6
7
8
9
10
B
C
N
O
F
Ne
13
14
15
16
17
18
Na Mg 3
4
5
6
7
8
9
10
11
12
Al
Si
P
S
Cl
Ar
19
20
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
K
Ca Sc
Ti
V
Cr
Mn Fe
Co Ni
Cu Zn
Ga Ge As
Se
Br
Kr
37
38
39
40
41
42
43
45
47
48
49
50
51
52
53
54
Rb Sr
Y
Zr
Nb Mo Tc
Ru Rh Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
55
56
57-71
72
73
74
75
76
78
79
80
81
82
83
84
85
86
Cs
Ba
La
Hf
Ta
W
Re Os Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
87
88
89-103
104
105
106
107
Fr
21
Ra Ac
57
58
59
Lanthanides La Ce Pr
Actinides
60
46
77
112
108
107
108
109
110
111
112
Bh
Hs
Mt
Ds Rg
--
61
114
--
Bh Hs
Db Sg
Rf
44
62
63
64
65
114
116
-66
67
68
69
70
71
Nd Pm Sm Eu
Gd Tb
Dy
Ho Er
Tm Yb
Lu
96
98
99
100
101
103
Cf
Es
Fm Md No Lr
89
90
91
92
93
94
95
97
Ac
Th
Pa
U
Np Pu Am Cm Bk
Techniques developed at PSI and Bern University
102
Reactions used and number of atoms found in the „first ever
chemical studies“ during the last decade
Bohrium (Z=107); Main experiments at PSI
249Bk(22Ne;4n)267Bh (T = 17 s); 6 atoms (R. Eichler et al., Nature, 407, 64 (2000))
1/2
Hassium (Z=108); Main experiments at GSI
248Cm(26Mg;5n)269Hs(T = 15 s); 7 atoms (C.E. Düllmann et al., Nature, 418, 860 (2002))
1/2
Element 112; Main experiments at FLNR/JINR
242Pu(48Ca,3n)287114 (T = 0.5 s)283112 (T = 4 s); 2 atoms (R. Eichler et al., Nature,
1/2
1/2
447, 72 (2007)). Confirmed with 3 additional atoms (R. Eichler et al., Angew. Chem. Int.
Ed., 47(17), 3262 (2008)
Element 114: Main experiments at FLNR/JINR
242,244Pu(48Ca;3,4n)287,288,289114 (T = 0.5s;0.8s;2.6s); 3 – 4 atoms (R. Eichler et
1/2
al.,submitted to Nature (2008)).
Mendeleev, Dubna 2009
How reliable is single atom chemistry?
1st example: hassium chemistry
Investigation of hassium in form of its very volatile molecule HsO4
Applied technique: Thermochromatography
Mendeleev, Dubna 2009
Thermochromatography
Internal chromatogram
Temperature gradient
T=100K
T
yield
T=300K
Tdep
detectors
length
Result:
Tdep  DHads
Thermochromatography of
OsO4 and HsO4
-44±5 °C
Rel. Yield [%]
80
70
4 atoms
-82±5 °C
HsO4
60
Exp: 172Os (T1/2=19.2 s)
MCS (Os): -39.5 kJ/mol
MCS (Hs): -46.5 kJ/mol
Temperature profile
1 atom
0
-20
-40
-60
-80
OsO4
50
40
Exp:269Hs (T1/2 =9.7 s)
-100
2 atoms
-120
30
-140
20
-160
10
-180
0
-200
1
2
3
4
5
6
7
8
Detector
C.E. Düllmann et al., Nature 418,860 (2002)
9
10 11 12
Temperature [°C]
90
Nobel Laureate Glenn T. Seaborg,
The first human being, able to celebrate „his“ element!
Mendeleev, Dubna 2009
How reliable is single atom chemistry?
2nd example: element 112
Element 112 presumably is highly volatile so that it can be
separated and analysed in elemental form
Applied technique: Thermochromatography
Mendeleev, Dubna 2009
Periodic Table today
1
18
1
2
H
2
13
14
15
16
17
He
3
4
5
6
7
8
9
10
Li
Be
B
C
N
O
F
Ne
11
12
13
14
15
16
17
18
Na Mg 3
4
5
6
7
8
9
10
11
12
Al
Si
P
S
Cl
Ar
19
20
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
K
Ca Sc
Ti
V
Cr
Mn Fe
Co Ni
Cu Zn
Ga Ge As
Se
Br
Kr
37
38
39
40
41
42
43
45
47
48
49
50
51
52
53
54
Rb Sr
Y
Zr
Nb Mo Tc
Ru Rh Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
55
56
57-71
72
73
74
75
76
78
79
80
81
82
83
84
85
86
Cs
Ba
La
Hf
Ta
W
Re Os Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
87
88
89-103
104
105
106
107
115
116
116
Fr
21
Ra Ac
57
58
59
Lanthanides La Ce Pr
Actinides
60
46
77
112
108
61
114
--
Bh Hs
Db Sg
Rf
44
62
109
110
Mt
Ds Rg
63
111
64
114
113
65
66
67
68
69
118
70
71
Nd Pm Sm Eu
Gd Tb
Dy
Ho Er
Tm Yb
Lu
96
98
99
100
101
103
Cf
Es
Fm Md No Lr
89
90
91
92
93
94
95
97
Ac
Th
Pa
U
Np Pu Am Cm Bk
102
Trend of sublimation enthalpy within group 12
160
Zn
140
DHsubl, kJ/mol
120
Cd
100
Hg
80
60
Mendeleev says: 112 an even
more volatile metal compared to
Hg!
40
20
?112
0
0
20
40
60
Z
80
100
120
However,…..
• Pitzer (1975) says: because of relativistic
effects element 112 could well behave like a
noble gas.
• Reason: E112 has a filled 6d107s2 electronic
shell configuration
Relativistic effects
• High atomic number: strong Coulomb attraction
causes electrons to move faster.
• Causes relativistic mass increase [m=m0(1-b2)],
with b=v/c; and, as a consequence, contraction of
spherical orbitals (ns, np1/2)
• Energy levels of spherical orbitals are increased
• Energy levels of high angular momentum orbitals
are destabilized due to shielding effects by spherical
orbitals
• Strong spin-orbit splitting
Courtesy:P. Schwerdtfeger
Example: the relativistic 6s/7s contraction in Au and Rg
0.5
4 r 2 (r)
h2
h2
v2
aB =
=
1  2 = aB0
2
2
mc
m0 c
c
7s
R
0.4
v2
1 2
c
Consequence: Cu, Ag, Au nd10(n+1)s1
6s
R
Zn+,Cd+,Hg+
however: Rg, 112+ nd9(n+1)s2 (2D5/2)
0.3
6s
NR
0.2
7s
NR
0.1
r (a.u.)
0.0
0
1
2
3
4
5
6
7
E.Eliav, U.Kaldor, P.Schwerdtfeger, B.Hess, Y.Ishikawa, Phys. Rev. Lett. 73, 3203 (1994).
M.Seth, P.Schwerdtfeger, M.Dolg, K.Faegri, B.A.Hess, U.Kaldor, Chem. Phys. Lett. 250, 461 (1996).
Relativistic Effects
P. Pyykkö
direct effect
(contraction)
indirect effect
(expansion)
relativistic
nonrelativistic
M.Kaupp, Spektrum der Wissenschaften, 2005
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
Metal Surface
Surface: Gold
50
500
45
450
Hg-192 Hads = -87 kJ/mol
400
Rn-219 Hads = -27 kJ/mol
35
350
30
300
25
250
20
200
15
150
10
100
5
50
0
0
1
3
5
7
9
11
13
15
17 19
lenght [cm]
21
23
25
27
29
31
temperature [K]
yield [%]
40
Quartz Surface
60
Hg-192 Hads = -24.5 kJ/mol
Rn-219 Hads = -20.5 kJ/mol
400
350
40
yield [%]
450
300
30
Tdep. Tl, Po, Pb, Bi ≥ 500 K
20
250
200
150
100
10
50
0
0
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 32
lenght [cm]
temperature [K]
50
500
The EPIPHANIOMETER
(Teflon)
for 211Pb (via 211Bi)
219Rn
211Pb
No 211Pb detected for clean gas (no aerosol particles)
H.W. Gäggeler et al., J. Aerosol Sci., 20, 557 (1989)
Application to atmospheric aerosol detection at exotic sites
The element 112,114 experiments
(IVO Technique)
Beam (48Ca)
Window/
Target
(242,244Pu)
Recoil
chamber
Teflon
capillary
SiO2-Filter
Ta metal
850°C
Beam
stop
Quartz
inlay
Cryo On-line Detector (4 COLD)
(32 pairs PIN diodes, one side gold covered)
Hg
Quartz
column
112,114?
Loop
Rn
Temperature gradient: 35°C to – 180 °C
T
Carrier gas
He/Ar (70/30)
l
The E112 experiments in 2006/2007
Reported at FLNR:
291116
Oganessian et al. 2004
6.3 ms
10.7 MeV
287114
0.51 s
10.02 MeV
283112
Observed in Chemistry:
242Pu (48Ca,
3n) 287114
6.2•1018 48Ca during eff. 32 days
(8 weeks absolute)
283112
283112
283112
283112
283112
9.38 MeV
9.47 MeV
9.52 MeV
9.35 MeV
9.52 MeV
4s
9.54 MeV
279Ds
279Ds
279Ds
279Ds
279Ds
279Ds
0.18 s
SF(>90%)
205 MeV
t: 0.592 s
SF
t: 0.536 s
SF
t: 0.072 s
SF
t: 0.773 s
SF
t: 0.088 s
SF
112+n.d. MeV
85+12 MeV
94+51 MeV
108+123 MeV 127+105 MeV
NR <1E-5
NR =0.05
Monte Carlo simulation
Results for
one single component
50
50
185
40
ice
gold
Hg
30
50
Rn
20
-50
20
ice
gold
0
219
(-28°C)
30
-50
283
-100
112
-100
10
10
-150
-150
-200
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
50
185
40
Hg
gold
50
ice
219
30
Rn
0
-50
20
(-5°C)
-100
10
-150
0
-200
Temperature, °C
Rel. yield / detector, %
Rel. yield / detector, %
0
30
gold
40
30
20
gas flow
ice
0
20
283
-50
112
-52+4
10
-3
kJ/mol
50
219
Hg
(-21°C)
(-39°C)
Rn
0
-200
30
gold
ice
-50
10
-100
-50
112
-100
10
-150
0
-200
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Detector #
50
0
20
283
(-124°C)
-100
-150
0
185
50
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
50
ice
-200
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
gold
0
-150
0
-200
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Courtesy: R. Eichler
Detector #
Temperature, °C
Experiment
250
Po Pb
experimantal data
least square fit:
95% c.i.
Tl
Bi
-DHads(Au), kJ/mol
200
150
Hg
100
At
Xe
50
Rn
-DHads(Au) = (1.08±0.05)*DHsubl+(10.3±6.4), kJ/mol
Kr
0
0
50
100
150
DHsubl, kJ/mol
200
250
Trend of sublimation enthalpy within group 12
160
Zn
140
DHsubl, kJ/mol
120
Cd
100
Hg
80
60
40
112
20
0
0
20
40
60
Z
80
100
120
Production of E114
242Pu (48Ca,
244Pu (48Ca,
3n) 287114
3-4n) 288-289114
287114
288114
289114
0.51 s
10.02 MeV
0.8 s
2.6 s
9.95 MeV
9.82 MeV
283112
284112
285112
4s
0.097 s
SF
29 s
9.54 MeV
279Ds
281Ds
0.2 s
SF
11 s
SF
9.16 MeV
Yu.Ts. Oganessian et al., 2004
120
DH°298 [kcal/mol]
Standard
enthalpies
of gaseous
monoatomic
elements
100
80
60
40
20
0
0
20
40
60
80
100
120
Atomic number
B. Eichler, 1974
Results with element 114
Dubna 2007 - 2008
244Pu (48Ca, 3-4n) 288-289114
242Pu (48Ca, 3n) 287114
3.1•1018 48Ca during 16 days
283112
t: 10.93 s
a 9.53
1.43•1019 48Ca during 51 days
287114
288114
288114
10.04 MeV
9.95 MeV
9.81 MeV
284112
Det#4
285112
284112
t: 0.11 s
SF 62+n.d.
NR=1.5E-3
279Ds
t: 0.242 s
SF 114+103
NR=2E-2
NR=1.1E-2
t: 0.10 s
SF 108+n.d.
Det#6
281Ds
t: 3.38 s
SF 106+44
NR=1.8E-3
9.20 MeV
289114
15
12
9
6
3
0
15
12
9
6
3
0
15
12
9
6
3
0
287
114
gold
ice
-88°C
-4°C
288
( 114)
288
50
0
-50
-100
-150
-200
114
-90°C
289
285
( 114--> 112)
Z=112
50
0
-50
-100
-150
-200
-93°C
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Detector #
50
0
-50
-100
-150
-200
Temperature, °C
Rel. yield / detector, %
Results (2007/2008)
Prediction and exp. result
Dubna 2007/2008
250
E114 M
150
-D H
M
ads
200
B. Eichler 2003
R. Eichler et al. 2002
V.Pershina et al 2008
100
50
E114 G
114Exp(2007/2008)
0
Cu
Ag
Au
metal
Pd
Ni
Strong stabilization of elemental 6d107s27p1/22 atomic state!
How to interpret low adsorption
enthalpy of E114?
Unexpected observation: E114
significantly different to Pb and even
more volatile than E112.
Calculated van der Waals energies
using covalent radii1, polarizabilities2
and ionisation potentials2
1P.Pyykkö,
2
M. Atsumi, Chem.Eur. J., 2009, 15, 186
E=114: C. Thierfelder, B. Assadollahzadeh, P. Schwerdtfeger,
S. Schäfer, R. Schäfer, Phys. Rev. A 78, 052506 (2008)
E=112: V.Pershina, A. Borschevsky, E. Eliav, U. Kaldor, J.
Chem. Phys. 128, 024707 (2008)
E112 on Au: -30 kJ/Mol; exp.: -52 kJ/Mol
E114 on Au: -23 kJ/Mol; exp.: -34 kJ/Mol
(Rn on Au: - 24 kJ/Mol; exp.: -27 kJ/Mol)
Courtesy: R. Eichler
Conclusion
- On-line
gas phase chemistry has reached the sensitivity of
about 1 pb
- Month-long beam times at highest possible beam intensities
mandatory for chemical studies
- Single atom chemistry yields reliable chemical information
- Elements 112 and 114 surprisingly volatile
- Next: element 113 (eka-Tl). Expected volatility of At.
- Far future: chemistry from actually s-range to ms-range?
(e.g. Stern-Gerlach experiment for atomic electronic
configuration) [Proposal E.K. Hulet]
Acknowledgement
- Excerpt for Z=112/114 studies PSI team: R. Eichler et al.
FLNR chemistry: S. Dmitriev, S. Shishkin
FLNR GNS team: V.K. Utyonkov et al.
FLNR VASSILISSA team: A.V. Yeremin et al.
FLNR support: Yu. Ts. Oganessian
LLNR target: K.J.Moody et al.
Adsorption of E112 on Au
-DH
M
ads
, kJ/mol
120
E112
Metal
100
80
Tdep °C
Hg
140
100
E112calc
25
60
-52+4
-3
kJ/mol
Rn
E112
Gas
40
20
0
Cu
Ag
Au
metal
Pd
-180
B. Eichler 1985
B. Eichler 2003
Ni
V. Pershina et al. 2005/08
R. Eichler et al. 2002
R. Eichler
et al. 2002
Eichler, R. et al. Nature 487, 72 (2007)
Result can be used to improve the prediction models