Pauli energy contribution to the nucleus-nucleus interaction

Abstract

Attempts to understand effects of the Pauli exclusion principle in nucleus-nucleus potentials and the resulting barrier to fusion have a long history. The authors propose a method to quantify the Pauli kinetic energy that allows one to distinguish between neutron and proton contributions. Their analysis suggests that Pauli repulsion effects occur primarily in the ``neck'' between fragments at a distance of approach comparable to the barrier radius. Moreover, inside the barrier neutron contributions dominate in neutron-rich systems, which hinders sub-barrier fusion.