Shape coexistence in 76Se within the neutron–proton interacting boson model

Abstract

We have investigated the low-lying energy spectrum and electromagnetic transition strengths in even–even 76Se using the proton–neutron interacting boson model (IBM-2). The theoretical calculation for the energy levels and E2 and M1 transition strengths is in good agreement with the experimental data. Specifically, the excitation energy and E2 transition of state, which is intimately associated with shape coexistence, can be accurately reproduced. The analysis on low-lying states and the key structure indicators R 1, R 2, R 3 and R 4 and M1 transitions indicates that there is a coexistence between spherical shape and γ-soft shape in 76Se.