Coexistence of shapes and the role of the g_9/2 orbit in Se isotopes

Abstract

The phenomenon of the coexistence of nuclear shapes in ^70,72,74Se is studied within the framework of the deformed configuration mixing shell model. In this model, ⁵⁶Ni is taken as the core with the valence space consisting of 1p_3/2, 1p_1/2, 0f_5/2 and 0g_9/2 orbitals. An effective interaction given to Kuo and modified by Ahalpara and others has been used. The crossing of a nearly spherical ground state band and a highly deformed band in ^70,72Se are given by the calculation in agreement with experiment. The calculation does not show any such band crossing in ⁷⁴Se. The role of the g_9/2 orbital in producing highly deformed two neutron aligned bands is stressed.