Evolution of Neutron Shell Structure of \({N=14}\), \({16}\) Isotones

Abstract

The evolution of the single-particle characteristics of neutron- and proton-rich isotones with the new magic numbers \(N=14\), \(16\) in the \(Z\) range from 8 to 20 in the dispersive optical model was traced. The calculated energy gaps \(N=14\) and \(16\) widened with the increase in excess of protons and neutrons, respectively. At the same time, the deviation of half-sum of the single-particle energies of the last predominantly occupied and the first predominantly unoccupied states from the Fermi energy decreased. The widening of the gaps were enhanced under the assumption of an increase in the diffuseness of the Hartree–Fock component of the dispersive optical model potential with an increase in the neutron excess over the range of \(Z\) numbers considered. The bubble structure manifests itself clearly in the neutron density distribution of the proton-unstable nucleus \({}^{34}\)Ca.