NUMBER PROJECTED TWO-NEUTRON SEPARATION ENERGY IN THE NEUTRON-RICH RARE-EARTH REGION

Abstract

The variation of the two-neutron separation energy (S2N), as a function of the neutron number N, is studied using a microscopic model that includes the pairing effects rigorously within the Fixed-Sharp-BCS method. The model was first tested on "ordinary" nuclei and allowed one to suitably reproduce the experimental data and to confirm the results of previous studies. The model was then applied to the even–even neutron-rich isotopes in the rare-earth region and showed, on the one hand, a relatively important variation of S2N, when N = 100, that could lead to the assumption of the existence of a new magic number in this region, and on the other hand, a weak variation of S2N when N > 100. These findings corroborate the previously obtained results for the charge mean square radius and the quadrupole and hexadecapole moments within the same model.