Nuclear charge radii and shape evolution of Kr and Sr isotopes with the deformed relativistic Hartree-Bogoliubov theory in continuum

Abstract

The deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) is employed to study the ground-state properties of Kr and Sr isotopes. Based on the constrained DRHBc calculations, it is found that Kr and Sr isotopes with $N=50$ are spherical, while the nuclei just away from $N=50$ generally have soft potential energy curves. Further moving along the isotopic chains in both neutron-rich and neutron-deficient directions, there are generally two minima at oblate and prolate sides for nuclear potential energy curves, where possible candidates for shape coexistence are found. The dynamical correlations are crucial to describe the properties of nuclei with soft potential energy curves or shape coexistence, e.g., the binding energies, two-neutron separation energies, deformations, and charge radii, which are considered with the two-dimensional collective Hamiltonian method. In addition, the constrained DRHBc calculations would be helpful to distinguish the oblate or prolate shape for the nuclei with deformation $|{\ensuremath{\beta}}_{2}|\ensuremath{\gtrsim}0.3$ by combining with the experimental charge radii and absolute values of deformations.