Microscopic Dynamics of Shape Coexistence Phenomena around 68Se and 72Kr

TL;DR

This paper applies the ASCC method to study shape coexistence in proton-rich nuclei 68Se and 72Kr, revealing the collective pathways and calculating energy spectra and transition probabilities.

Contribution

It is the first to construct a quantum collective Hamiltonian and analyze shape coexistence phenomena using the ASCC method in these nuclei.

Findings

Collective path runs along a triaxial valley in the beta-gamma plane.

Low-lying energy spectra and E2 transition probabilities are well reproduced.

Effects of the time-odd pair field on collective mass and moments of inertia are clarified.

Abstract

The adiabatic self-consistent collective coordinate (ASCC) method is applied to the pairing-plus-quadrupole (P + Q) model Hamiltonian including the quadrupole pairing, and the oblate-prolate shape coexistence phenomena in proton-rich nuclei, 68Se and 72Kr, are investigated. It is shown that the collective path connecting the oblate and prolate local minima runs along a triaxial valley in the beta-gamma plane. Quantum collective Hamiltonian is constructed and low-lying energy spectra and E2 transition probabilities are calculated for the first time using the ASCC method. Basic properties of the shape coexistence/mixing are well reproduced. We also clarify the effects of the time-odd pair field on the collective mass (inertial function) for the large-amplitude vibration and on the rotational moments of inertia about three principal axes.