Search for shape-isomers in the Pt-Hg-Pb region

TL;DR

This study investigates shape-isomeric states in Pt, Hg, and Pb isotopes around 186Pt using a macroscopic-microscopic model to analyze potential energy surfaces and nuclear deformations, revealing multiple shape-isomers and their stability.

Contribution

It introduces a Fourier-over-Spheroid shape parametrization and compares shape-isomer predictions with HFB theory, enhancing understanding of nuclear shape coexistence.

Findings

Identification of multiple shape-isomers in Pt, Hg, and Pb isotopes.

Close agreement of potential energy surfaces with HFB calculations.

Emphasis on the importance of shape orientation in non-axial deformations.

Abstract

Potential energy surfaces of nine even-even isotopes of Pt, Hg, and Pb around $^{186}$Pt are evaluated within a macroscopic-microscopic model based on the Lublin-Strasbourg-Drop macroscopic energy and the microscopic energy obtained using the Yukawa-folded mean-field potential to establish the Strutinski shell corrections and the pairing correlation energy through the BCS approach with a monopole pairing force. The rapidly converging Fourier-over-Spheroid shape parametrization is used to describe nuclear deformations. The stability of the identified shape isomeric states with respect to non-axial and higher-order deformations is investigated. It is also found that in the description of non-axial deformations special attention needs to be devoted to the orientation of the triaxial shape. For the example of the $^{186}$Hg nucleus, where three prolate shape-isomeric states are found, it is shown that the potential energy surface obtained in our model is close to the one obtained in the Hartree-Fock-Bogoliubov theory with the Gogny energy-density functional.