Lifetimes of intruder states in Pb-186, Pb-188 and Po-194

摘要

Lifetimes of prolate intruder states in Pb-186 and Pb-188 and oblate intruder states in Po-194 have been determined through recoil distance Doppler-shift lifetime measurements. Deformation parameters Of vertical bar beta(2)vertical bar = 0.29(5) and vertical bar beta(2)vertical bar = 0.17(3) have been extracted from experimental B(E2) values for the prolate and the oblate bands, respectively. The present study addresses the phenomenon of shape coexistence typical for the nuclei near Z = 82 and N = 104, providing information on configuration mixing of intrinsic structures of the nuclei of interest. The results are compared with the available lifetime data and theoretical results for neutron-deficient Po, Pb, Hg and Pt nuclei. Furthermore, new self-consistent mean-field calculations have been carried out for Po-194. (c) 2008 Elsevier B.V. All rights reserved.