Spin-orbit interaction near the neutron drip line and shell effects at N = 82 near the r-process path

Abstract

We have studied the behavior of charge and neutron radii across the shell-closure at N = 82 near the neutron dripline in a comparative approach which includes Relativistic Mean Field (RMF) Theory and the nonrelativistic Skyrme-Hartree-Fock (SHF) Theory. We have investigated the extent and the effects of the spin-orbit interaction on the ground state properties of neutron-rich nuclei in the extreme region. RMF and SHF calculations have been performed for nuclei in the isotopic chains from Kr (Z = 36) to Sn (Z = 50) near the neutron dripline across the magic number N = 82. We present the results of shell-effects on charge radii, neutron radii, and the neutron skin thickness. We have examined the single particle energies (SPE) in the context of the kinks in the radii. It is shown that RMF theory produces a kink in charge radii, similar to what was seen experimentally for Pb (Z = 82) isotopic chains. This is in contrast to the Skyrme forces, which do not produce such a kink.