Single-particle structure of the N = 20, 28 isotones within the dispersive optical model

Abstract

The neutron single-particle characteristics of the $ N = 20, 28$ isotones at $ 8 < Z < 30$ were calculated within the dispersive optical model. The global parameters of the spin-orbit and imaginary parts of the potential as well as surface absorption independent on neutron-proton asymmetry and increased diffuseness at large neutron excess were used in the calculations. The suitability of the global parameters to predict the evolution of the neutron single-particle structure of nuclei near the neutron drip line was investigated. The following results are in agreement with the available experimental data: the reduction of the particle-hole energy gaps, the degeneration of the $ 1f_{7/2}$ and $ 2p$ states and then a change in the $ 1f_{7/2}$, $ 2p_{3/2}$ level sequence and more rapid reduction of the $ 2p$-splitting in comparison with the $ 1f$-splitting with Z decreasing. The predictive power of the dispersive optical model with respect to neutron-rich nuclei is demonstrated.