A shell-model interpretation of intruder states and the onset of deformation in even-even nuclei

Abstract

By simple consideration of the relative magnitude of the proton-neutron interaction (especially the monopole and quadrupole components) and the energy gaps between spherical shell-model states near shell and subshell closures, a shell-model interpretation of both the occurrence of low-lying intruder states in certain mass regions and of the onset of stable deformation in the ground state in others, is obtained. It is shown that in the Cd region near A ≅ 114, spherical ground states with low-lying intruder 0 + configurations result whereas deformation should occur in the A ≅ 100 ( Z = 40) and the A ≅ 150 ( Z = 64) mass regions.