Shell evolution in neutron-rich nuclei: the single particle perspective

The isospin dependence of spin-orbit (SO) splitting has become increasingly important as N/Z increases in neutron-rich nuclei. Following the initial independent-particle strategy towards explaining occurrence magic numbers, we have systematically investigated effect on shell evolution nuclei within Woods-Saxon (WS) mean-field potential plus term. It is found that new numbers N = 14 and =16 may emerge if one changes sign isospin-dependent term coupling while traditional number 20 disappear. 28 expected to be destroyed despite choice part splitting, corresponding strength SO Meanwhile, 50 82 shells persist single particle scheme, although there decreasing trend for their gaps extreme proton-deficient Besides, an appreciable energy gap appears at 32 34 Ca isotopes. All these results are more consistent with those interacting model, when enhancing independent model. present study provide a reasonable starting point not only model but also other nuclear many-body calculations neutron-dripline Segre chart.