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

Lifetimes of prolate intruder states in 186Pb and 188Pb and oblate intruder states in 194Po have been determined through recoil distance Doppler-shift lifetime measurements. Deformation parameters of | β2 | = 0.29 (5) and | β2 | = 0.17(3) have been extracted from experimental B (E 2) 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 194Po. © 2008 Elsevier B.V. All rights reserved.