Comparison of Cd and Hg level structures with regard to shape coexistence and shell quenching

Abstract

The lack of a drop in the excitation energy ratios and the anomaly of E(2+) energies in the even A Cd isotopes near the r-process waiting point nuclei of 130Cd also are observed in the even A Hg isotopes near 206Hg with N = 126. Because shape coexistence exists in Hg isotopes, Cd isotopes near N = 82 are proposed to have a similar shape coexistence. In the present work, it is shown that the state mixing of ground and excited bands can reproduce level energies observed in Hg and Cd isotopes. Experimental Qβ values of 130Cd and 132Sn are on the extrapolated lines without unusual raising or lowering. Therefore, it is concluded that shape coexistence can explain band structures of neutron-rich Cd and Hg isotopes without any need for shell quenching.