Shape coexistence in the neutron-deficient lead region: A systematic study of lifetimes in the even-even Hg188-200 with the GRIFFIN spectrometer at TRIUMF

摘要

Lifetimes of 2(1)(+) and 4(1)(+) states as well as some negative-parity and nonyrast states in Hg188-200 were measured using gamma-gamma electronic fast timing techniques with the LaBr3(Ce) detector array of the GRIFFIN spectrometer. The excited states were populated in the epsilon/beta(+) decay of J(pi) = 7(+)/2(-) 188-200Tl produced at the TRIUMF-ISAC facility. The deduced B(E2) values are compared to different interacting boson model predictions. The precision achieved in this paper over previous ones allows for a meaningful comparison with the different theoretical models of these transitional Hg isotopes, which confirms the onset of state mixing in Hg-190.