Speaker
Dr
Maxim Seliverstov
(Institut fuer Physik, Johannes Gutenberg Universitaet, Mainz)
Description
Shape coexistence at low excitation energy in nuclei has continuously shown
much interest on both experimental and theoretical fronts. The region around
the neutron mid-shell (N = 104) and closed proton shell (Z = 82) is of special
interest. For example, in Pb at N = 104, it has been found that the three
lowest lying states have 0+ as spin and parity values, these states have been
associated with different shapes in the nucleus: spherical and deformed
(prolate and oblate). Significant mixing of the deformed states into spherical
ground state would result in an increased nuclear charge radius.
At ISOLDE laser spectroscopy studies of neutron deficient isotopes (and
isomers) of Pb and Bi have been extended to N=100-107 (Pb) and N=106,108
(Bi). The measured values of the mean charge radius variations and nuclear
magnetic moments will be presented and compared with the recent theoretical
calculations (for Pb isotopes: IBM and beyond mean field calculations). Our data
support the predominantly spherical shape of the ground state of the Pb
isotopes near the neutron mid-shell (N=104).
The results of the first tests of photoionization schemes for Po will also
presented.
Author
Dr
Maxim Seliverstov
(Institut fuer Physik, Johannes Gutenberg Universitaet, Mainz)
