Study of shape coexistence in the 180−190Hg isotopes by SO(6) representation of eigenstates

Abstract

In this paper, we have studied the shape coexistence in the 180−190 Hg isotopes. The SO(6) representation of eigenstates and a transitional Hamiltonian in the Interacting Boson Model (IBM) are used to consider the evolution from prolate to oblate shapes for systems with total boson number N = 9−12. Parameter free (up to overall scale factors) predictions for energy spectra and quadrupole transition rates are found to be in good agreement with experimental counterparts. The results for the control parameter of transitional Hamiltonian offer a combination of spherical and deformed shapes in these Hg isotopes and also more deviation from SO(6) limit is observed when the quadrupole deformation is decreased. Also, there are some suggestions about the expectation values of then d operator which are determined in the first state of ground, beta and gamma bounds and the control parameter of model.