Collective-model description of shape coexistence and intruder states in cadmium isotopes based on a relativistic energy density functional

TL;DR

This paper models the low-energy nuclear structure of cadmium isotopes using a collective approach based on relativistic density functional theory, successfully reproducing vibrational and intruder states.

Contribution

It introduces a collective model grounded in relativistic energy density functional theory to describe shape coexistence and intruder states in cadmium isotopes.

Findings

Reproduces observed quadrupole phonon states

Identifies low-lying intruder bands consistent with empirical data

Accurately predicts energy spectra and transition probabilities

Abstract

Low-energy structure of even-even $^{108-116}$Cd isotopes is analyzed using a collective model that is based on the nuclear density functional theory. Spectroscopic properties are computed by solving the triaxial quadrupole collective Hamiltonian, with parameters determined by the constrained self-consistent mean-field calculations within the relativistic Hartree-Bogoliubov method employing a universal energy density functional and a pairing force. The collective Hamiltonian reproduces the observed quadrupole phonon states of vibrational character, which are based on the moderately deformed equilibrium minimum in the mean-field potential energy surface. In addition, the calculation yields a low-lying excited $0^+$ band and a $\gamma$-vibrational band that are associated with a deformed local minimum close in energy to the ground state, consistently with the empirical interpretation of these bands as intruder bands. Observed energy spectra, $B(E2)$, and $\rho^2(E0)$ values are, in general, reproduced reasonably well.