1. CERN, August 2008

2. HAPPY LANDING ON THE ISLAND OF SUPERHEAVY ELEMENTS Heinz W. Gäggeler Paul Scherrer Institut and Bern University, Switzerland Laboratory for Radiochemistry and Environmental Chemistry

3. sea of instability island of Superheavy Elements Number of neutrons Number of protons 20 50 82 114 20 82126 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)

4. CERN, August 2008 Shell stabilisation Courtesy: S. Hofmann deformed spherical

5. CERN, August 2008 Courtesy: M. Schädel The Dubna claims using 48 Ca induced fusion reactions with actinides targets

6. Periodic Table of the Elements Ds H Li Na K Rb Cs FrRaAc Ba Sr Ca Mg Be Sc Y La Ti Zr Hf V Nb Ta Cr Mo W Mn Tc Re Fe Ru Os CoNiCuZnGaGeAs RhPdAgCdInSnSb IrPtAuHgTlPbBi RfDb Sg BCNOF AlSiPSCl SeBr TeI PoAt 8788 89 104105 106 555657727374757677 3738394041424344454647484950515253 7879808182838485 1920212223242526272829303132333435 11121314151617 34 1 56789 1 2 3456789101112 1314151617 CePrNdPmSmEuGdTbDyHoErTmYbLu ThPaUNpPuAmCmBkCfEsFmMdNoLr 58 90 59606162 91929394 63 9596979899100101 646566676869 102103 7071 Lanthanides Actinides Bh 107 Hs Mt 108 109110 Rg 111 112 114116 -- He Ne Ar Kr Xe Rn 54 86 36 18 10 2 18 113 114 115 116 118

7. H Li Na K Rb Cs FrRaAc Ba Sr Ca Mg Be Sc Y La Ti Zr Hf V Nb Ta Cr Mo W Mn Tc Re Fe Ru Os CoNiCuZnGaGeAs RhPdAgCdInSnSb IrPtAuHgTlPbBi RfDb BCNOF AlSiPSCl SeBr TeI PoAt 8788 89-103 104105 555657-71727374757677 3738394041424344454647484950515253 7879808182838485 1920212223242526272829303132333435 11121314151617 34 1 56789 1 2 3456789101112 1314151617 Lanthanides Actinides 114 - 116 - He Ne Ar Kr Xe Rn 54 86 36 18 10 2 18 CePrNdPmSmEuGdTbDyHoErTmYbLu ThPaUNpPuAmCmBkCfEsFmMdNoLr 58 90 59606162 91929394 63 9596979899100101 646566676869 102103 7071 La Ac 57 89 Positioning of new elements into the Periodic Table Sg 106 Bh 107 Hs 108 Mt 109110 Ds Rg 112 - Sg 1062000 Bh 107 Hs 1082002 2001 - 2007 1993 - 1997 112 - 114 - ≥ 2007 111 113115116118

8. CERN, August 2008 Reactions used and number of atoms found in the „first ever chemical studies“ during the last decade Bohrium (Z=107); Main experiment at PSI 249 Bk( 22 Ne;4n) 267 Bh (T 1/2 = 17 s); 6 atoms (R. Eichler et al., Nature, 407, 64 (2000)) Hassium (Z=108); Main experiment at GSI 248 Cm( 26 Mg;5n) 269 Hs (T 1/2 = 15 s); 7 atoms (C.E. Düllmann et al., Nature, 418, 860 (2002)) Element 112; Main experiment at FLNR/JINR 242 Pu( 48 Ca,3n) 287 114 (T 1/2 = 0.5 s)  283 112 (T 1/2 = 4 s); 2 atoms (R. Eichler, Nature, 447, 72,2007); meanwhile 5 atoms in total (R. Eichler et al., Angew. Chem. Int. Ed., 47, 3262 (2008)) Element 114: Main experiment at FLNR/JINR; ongoing. Currently evidence for 4 atoms

9. Isothermal Chromatography: Sg,Bh Temperature [°C] Column length [cm] Temperature [°C] Yield [%] 50% T t Ret. = T 1/2 Gas flow highlow Thermochromatography: Hs, Z=112; Z=114 Temperature [°C] Column length [cm] Temperature [°C] Yield [%] T a high Gas flow low Example: Chemical study of bohrium Example: Chemical study of elements 112 and 114

10. CsCl aerosols reaction oven 118MeV 22 Ne 22 Ne 249 BkFUSION 271 Bh* 267 Bh 249 Bk HCl O2O2 He chromatography column Ar to detection system ROMA carbon aerosols reaction products On-Line Gas chromatography Apparatus Continuous on-line chemistry Example: bohrium

11. How to detect single atoms? Textbook example: Discovery of element 112 SHIP 9.2.1996 22:37 SHIP 9.2.1996 22:37 277 112 11.45 MeV 280  s 1111 273 110 11.08 MeV 110  s 2222 269 Hs 9.23 MeV 19.7 s 3333 265 Sg 4.60 MeV (escape) 7.4 s 4444 261 Rf 8.52 MeV 4.7 s 5555 257 No 8.34 MeV 15.0 s 6666 70 Zn + 208 Pb → 277 112 + 1n

12. First chemical characterization of bohrium (Z=107) bohrium (Z=107) T isothermal (°C) -20020406080100120140160180200220 Relative yield (%) 0 20 40 60 80 100 120 140 160 TcO 3 Cl 108 (T 1/2 = 5.2 s) H a = -51 kJ/mol  (T 1/2 = 16 s) ReO Cl 3 169  H a = -62 kJ/mol BhO 3 Cl 267 (T 1/2 = 17 s) = -75 +9 -6 kJ/mol H a  0 atoms 2 atoms 4 atoms R. Eichler et al., Nature, 407, 63 (2000)

13. Elements with Z ≥ 112: filled 6d 10 shell: 7p-element behaviour (volatile noble metals) Ds H Li Na K Rb Cs FrRaAc Ba Sr Ca Mg Be Sc Y La Ti Zr Hf V Nb Ta Cr Mo W Mn Tc Re Fe Ru Os CoNiCuZnGaGeAs RhPdAgCdInSnSb IrPtAuHgTlPbBi RfDb Sg BCNOF AlSiPSCl SeBr TeI PoAt 8788 89 104105 106 555657727374757677 3738394041424344454647484950515253 7879808182838485 1920212223242526272829303132333435 11121314151617 34 1 56789 1 2 3456789101112 1314151617 CePrNdPmSmEuGdTbDyHoErTmYbLu ThPaUNpPuAmCmBkCfEsFmMdNoLr 58 90 59606162 91929394 63 9596979899100101 646566676869 102103 7071 Lanthanides Actinides Bh 107 Hs Mt 108 109110 Rg 111 112 114116 -- He Ne Ar Kr Xe Rn 54 86 36 18 10 2 18 113 114 115 116 118

14. 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

15. Adsorption of single atoms of mercury and radon on a gold surface

16. Adsorption of single atoms of mercury and radon on a quartz surface

17. CERN, August 2008 Correlation between adsorption properties of single atoms on gold and their macroscopic sublimation enthalpy

18. Texas A&M, Nov. 2007 Ds H Li Na K Rb Cs FrRaAc Ba Sr Ca Mg Be Sc Y La Ti Zr Hf V Nb Ta Cr Mo W Mn Tc Re Fe Ru Os CoNiCuZnGaGeAs RhPdAgCdInSnSb IrPtAuHgTlPbBi RfDb Sg BCNOF AlSiPSCl SeBr TeI PoAt 8788 89 104105 106 555657727374757677 3738394041424344454647484950515253 7879808182838485 1920212223242526272829303132333435 11121314151617 34 1 56789 1 2 3456789101112 1314151617 CePrNdPmSmEuGdTbDyHoErTmYbLu ThPaUNpPuAmCmBkCfEsFmMdNoLr 58 90 59606162 91929394 63 9596979899100101 646566676869 102103 7071 Lanthanides Actinides Bh 107 Hs Mt 108 109110 Rg 111 112 114116 -- He Ne Ar Kr Xe Rn 54 86 36 18 10 2 18 113 114 115 116 118 Element 112 similar to Hg?

19. Window/ Target ( 242 Pu:  1.4 mg/cm 2 ) Beam ( 48 Ca; 233-239 MeV) Beam stop SiO 2 -Filter Ta metal 850°C Quartz column Cryo On-line Detector (4  COLD) Carrier gas He/Ar (70/30) Teflon capillary (32 pairs PIN diodes, one side gold covered) Hg Loop Temperature gradient: 35°C to – 184 °C T l Rn The element 112 experiment (IVO [In-situ Volatilisation and On-line detection] Technique) 112 Recoil chamber Quartz inlay

20. CERN, August 2008 Studies on element 112 242 Pu( 48 Ca;3n) 287 114 (0.5 s) → 4s 283 112 242 Pu( 48 Ca;3n) 287 114 (0.5 s) → 4s 283 112 Reasons a) High cross section of  5 pb ( 3-times higher than via direct production with 238 U as a target) Reasons a) High cross section of  5 pb ( 3-times higher than via direct production with 238 U as a target) b) Residence time in collection chamber and transport capillary  2 s b) Residence time in collection chamber and transport capillary  2 s 283 112  9.54 MeV 4 s Rf 261 4 s  8.5 MeV Ds 279 0.2 s

21. CERN, August 2008 xn-channel cross sections from 242,244 Pu+ 48 Ca reactions Excitation functions Courtesy: Yu. Oganessian. “Heaviest Nuclei from 48 Ca-induced Reactions” TAN-07, Davos, Sept. 23-27, 2007

22. 283 112 9.37 MeV 287 114 279 Ds  : 0.592 s SF 108+123 MeV Observed in Chemistry: 11.05.2006 2:40 (moscow time) 283 112 9.48 MeV 287 114 279 Ds  : 0.536 s SF 127+105 MeV 25.05.2006 8:37 (moscow time) Result from the 48 Ca + 242 Pu experiment Laboratory for Radiochemistry and Environmental Chemistry Three week bombardment with 3.1 x 10 18 48 Ca ions at 236 ± 3 MeV First independent confirmation of 283 112 formation and decay properties! (R. Eichler et al., Nature, 447, 72 (2007))

24. 283 112 9.35 MeV 287 114 279 Ds  : 0.773 s SF 85+12 MeV Result from additional 48 Ca + 242 Pu experiments in 2007: 3 additional atoms from the 3n channel Bombardment 21.3.- 17.4. 2007 with 3.1x10 18 48 Ca ions at 237± 3 MeV 283 112 9.52 MeV 287 114 279 Ds  : 0.072 s SF 112 + n.d MeV 283 112 9.52 MeV 287 114 279 Ds  : 0.088 s SF 94+51 MeV The chemistry experiment is not sensitive to the 4n channel (too short-lived isotope)

25. The chemistry of element 112 Element 112 is similar to Hg, but slightly more volatile Deduced adsorption enthalpy: -52 +20 -4 kJ/mol (black solid line)

26. CERN, August 2008 The chemistry of element 112  H subl =39 +23 -10 kJ/mol (68% c.i.) -52 +20 -4 kJ/mol

27. CERN, August 2008 Trend of sublimation enthalpy within group 12

28. CERN, August 2008 What‘s next? Search for relativistic effects in the chemistry of element 114 (group 14 with [Rn]7s 2 6d 10 7p 2 ) Relativistic effect: influence of increasing Coulomb attraction between atomic electrons and nucleus

29. CERN, August 2008 Primary relativistic effect: s p 1/2 p 3/2 d 3/2 d 5/2 f 5/2 f 7/2 m= 1/2 m=-1/2 m= 1/2 m=-1/2 m= 3/2 m= 1/2 m= -1/2 m= -3/2 m= 5/2 m= 3/2 m= 1/2 m= -1/2 m= -3/2 m= -5/2 m= 7/2 m= 5/2 m= 3/2 m= 1/2 m= -1/2 m= -3/2 m= -5/2 m= -7/2 White 1931

30. CERN, August 2008 Secondary relativistic effect: s p 1/2 p 3/2 d 3/2 d 5/2 f 5/2 f 7/2 m= 3/2 m= 1/2 m= -1/2 m= -3/2 m= 5/2 m= 3/2 m= 1/2 m= -1/2 m= -3/2 m= -5/2 m= 7/2 m= 5/2 m= 3/2 m= 1/2 m= -1/2 m= -3/2 m= -5/2 m= -7/2 White 1931 Spin-Orbit splitting splitting m= 1/2 m=-1/2 m= 1/2 m=-1/2

31. from: V. Pershina et al., J. Chem. Phys., 127, 134310 (2007) Group 14: 6d 10 7s 2 7p 2 Prediction by Pitzer (1975) Is element 114 a noble gas due to a strong spin-orbit splitting of the 7p orbitals?

32. CERN, August 2008 Studies on element 114 Reaction: 242 Pu( 48 Ca;3n) 287 114 (T 1/2 =0.5s) (FLNR; spring 2007) Reaction: 242 Pu( 48 Ca;3n) 287 114 (T 1/2 =0.5s) (FLNR; spring 2007) Rf 261 4 s  8.5 MeV Ds 279 0.24s 283 112 287 114 10.9 s  9.54 MeV  10.0 MeV 1 atom on Au at – 80 °C 3.1 x 10 18 48 Ca ions at 237± 3 MeV unpublished

33. CERN, August 2008 Studies on element 114 Reaction: 244 Pu( 48 Ca;4n) 288 114 (T 1/2 =0.8s) Reaction: 244 Pu( 48 Ca;4n) 288 114 (T 1/2 =0.8s) Rf 261 4 s  8.5 MeV 2 atoms on Au at –10 °C & -84 °C Beam dose 4x10 18 Energy within targets: 243 – 231 MeV (~ 1.4 mg/cm 2 ) 288 114  9.95 MeV  9.81 MeV 284 112 0.11 s unpublished

34. Experiment April/May at FLNR: 48 Ca + 244 Pu to produce 0.8 s 288 114 (4n-channel) 2.7 s 289 114 (3n-channel) Chemistry behind the Dubna gas- filled separator

35. Pro & Contra Pro: - Extremely clean  - spectra (no background) - no sf-contamination by sputtered target Contra: - Lower efficiency (thin target & 35% sep.yield) - Smaller energy range in the thin target

36. CERN, August 2008 Studies on element 114 Reaction: 244 Pu( 48 Ca;3n) 289 114 (T 1/2 =2.7s) (FLNR; 2008) Reaction: 244 Pu( 48 Ca;3n) 289 114 (T 1/2 =2.7s) (FLNR; 2008) Rf 261 4 s  8.5 MeV 281 Ds 3.3s 285 112 289 114  9.12 MeV Not detected 1 atom on Au at – 97 °C 4 x 10 18 48 Ca ions at E* = 38 – 42 MeV SF 106+50 unpublished

37. Decay during transport? Preliminary unpublished

38. E114 Preliminary

39. Result from the chemistry experiment with element 114 → Element 114 exhibits a very weak adsorption on Au - pointing to a physisorptive van der Waals interaction (similar to a noble gas). Preliminary!

40. CERN, August 2008 Conclusion Chemical studies at the few atom level have been sucessfully conducted up to Z = 114 Chemical studies at the few atom level have been sucessfully conducted up to Z = 114 Elements Bh, Hs & 112 (as well as Rf, Db, Sg) behave in gas phase studies as expected from extrapolations within the groups of the periodic table Elements Bh, Hs & 112 (as well as Rf, Db, Sg) behave in gas phase studies as expected from extrapolations within the groups of the periodic table Ongoing studies point to an element 114 behaviour unlike that of eka-Pb, but rather similar to a noble gas. Ongoing studies point to an element 114 behaviour unlike that of eka-Pb, but rather similar to a noble gas.

41. CERN, August 2008 Acknowledgement Yuri Oganessian, Sergei Dmitriev and Georgi Gulbekian Yuri Oganessian, Sergei Dmitriev and Georgi Gulbekian Robert Eichler and his team from the PSI/Univ. Bern collaboration Robert Eichler and his team from the PSI/Univ. Bern collaboration