Spectroscopic calculations of the low-lying structure in exotic Os and W isotopes

TL;DR

This study uses a combination of the Interacting Boson Model and Hartree-Fock-Bogoliubov calculations to explore shape transitions and predict spectroscopic properties in neutron-rich Os and W isotopes, especially near N=126.

Contribution

It introduces a novel approach by mapping Gogny-EDF PES onto the IBM to study shape evolution in exotic isotopes, providing predictions where experimental data is scarce.

Findings

Prolate-to-oblate shape transition occurs rapidly in Os and W isotopes.

Predicted spectroscopic variables for neutron-rich W isotopes with limited experimental data.

Onset of shape transition is faster than in neighboring Pt isotopes.

Abstract

Structural evolution in neutron-rich Os and W isotopes is investigated in terms of the Interacting Boson Model (IBM) Hamiltonian determined by (constrained) Hartree-Fock-Bogoliubov (HFB) calculations with the Gogny-D1S Energy Density Functional (EDF). The interaction strengths of the IBM Hamiltonian are produced by mapping the potential energy surface (PES) of the Gogny-EDF with quadrupole degrees of freedom onto the corresponding PES of the IBM system. We examine the prolate-to-oblate shape/phase transition which is predicted to take place in this region as a function of neutron number $N$ within the considered Os and W isotopic chains. The onset of this transition is found to be more rapid compared to the neighboring Pt isotopes. The calculations also allow prediction of spectroscopic variables (excited state energies and reduced transition probabilities) which are presented for the neutron-rich $^{192,194,196}$W nuclei, for which there is only very limited experimental data available to date.