Shape coexistence and evolution in neutron-deficient krypton isotopes

TL;DR

This study uses Total Routhian Surface calculations to analyze shape coexistence and evolution in neutron-deficient krypton isotopes, revealing shape changes and the importance of triaxiality consistent with experimental data.

Contribution

It provides a detailed theoretical investigation of shape coexistence and evolution in krypton isotopes using TRS calculations, highlighting shape changes and the role of triaxiality.

Findings

Ground state shape changes from oblate to prolate across isotopes

Calculated quadrupole deformations match experimental data

Shape mixing and triaxiality are significant in low-spin states

Abstract

Total Routhian Surface (TRS) calculations have been performed to investigate shape coexistence and evolution in neutron-deficient krypton isotopes ${}^{72,74,76}$Kr. The ground-state shape is found to change from oblate in ${}^{72}$Kr to prolate in ${}^{74,76}$Kr, in agreement with experimental data. Quadrupole deformations of the ground states and coexisting $0^{+}_{2}$ states as well as excitation energies of the latter are also well reproduced. While the general agreement between calculated moments of inertia and those deduced from observed spectra confirms the prolate nature of the low-lying yrast states of all three isotopes (except the ground state of ${}^{72}$Kr), the deviation at low spins suggests significant shape mixing. The role of triaxiality in describing shape coexistence and evolution in these nuclei is finally discussed.