On-line separation of single atoms of elements 104 and 105 using isothermal gas phase chromatography

On-line isothermal gas phase chromatography was applied to separate single atoms of the isotopes 261104(T1/2 = 65 s) and 262105(T1/2 = 34 s) produced in complete fusion reactions of 95-MeV 18O projectiles with targets of 248Cm and 249Bk, respectively. Using HBr and HCl gas as reactive agents the authors were able to produce volatile bromides and chlorides of the above mentioned elements and study their behavior compared to their lighter homologs in Group 4 or Group 5. Surprisingly, element 104 formed very volatile bromides and chlorides compared to its homolog Hf. This may be indicative of a significant relativistic alteration of the electronic structure of this element. Modifications of the electronic structure of very heavy elements due to relativistic effects have been predicted theoretically. In contrast, element 105 bromides were shown to behave similarly to the bromides of the group 5 elements Nb and Ta, and the pseudo-group 5 element Pa