Shape coexistence close to $N=50$ in the neutron-rich isotope $^{80}$Ge investigated by IBM-2

TL;DR

This study uses the IBM-2 model to analyze low-lying states and shape coexistence in neutron-rich $^{80}$Ge near $N=50$, successfully reproducing experimental energy levels and predicting transition strengths.

Contribution

It provides a detailed theoretical analysis of shape coexistence in $^{80}$Ge using IBM-2, highlighting the coexistence of spherical and $ ext{γ}$-soft structures near $N=50$.

Findings

Reproduces experimental energy levels and $E2$ transition strengths accurately.

Predicts $E0$ transition strength $ ho^2(E0, 0^+_2 ightarrow 0^+_1)$.

Indicates coexistence of spherical and $ ext{γ}$-soft vibrational structures.

Abstract

The properties of the low-lying states, especially the relevant shape coexistence in $^{80}$Ge close to one of most neutron-rich doubly magic nuclei at $N=50$ and $Z=28$ have been investigated within the framework of the proton-neutron interacting model (IBM-2). Based on the fact that the relative energy of the $d$ neutron boson is different from proton bosons', the calculated energy levels of low-lying states, $E2$ transition strengths can reproduce the experimental data very well. Particularly, the first excited state 0$^+_2$ is reproduced quite nicely, which is intimately related with the shape coexistence phenomenon. And the $\rho^2(E0, 0^+_2\rightarrow0^+_1)$ transition strength has been predicted. The experimental data and theoretical results indicate that both collective spherical and $\gamma$-soft vibration structures coexist in $^{80}$Ge. Key words: $^{80}$Ge, low-lying states, $E0$ transition strengths, shape coexistence, IBM-2.