Shape Coexistence in the Pb Region

Abstract

By studying the β +/EC and α decay of mass—separated neutron—deficient Hg to Fr nuclei, the spectroscopy group at the Leuven Isotope Separator On Line (LISOL) project collected in recent years extensive systematics on shell—model intruder states in the Pb region 1–10. These shell—model intruder states, leading to shape coexistence, have been identified in odd—proton At, Bi and Tl nuclei 3–4, odd—neutron Pb nuclei 8 9, even — even Pb nuclei 1 2 5 7 and odd—odd Tl nuclei 6 10. A remarkable systematic behavior of the excitation energy of the intruder—based states as a function of neutron number is now evident and several theoretical descriptions have been developed to reproduce this specific trend (see the references 11 to 15 and the contributions to this conference by K. Heyde, R. Bengtsson and N. Tajima).KeywordsIsomeric StateMass SeparatorIntruder StateShape CoexistenceProlate DeformationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.