Structure analysis for hole-nuclei close to132Sn by a large-scale shell-model calculation

Abstract

The structure of neutron-rich nuclei with a few holes in respect of the doubly magic nucleus ${}^{132}$Sn is investigated by means of large-scale shell-model calculations. For a considerably large model space, including orbitals allowing both neutron and proton core excitations, an effective interaction for the extended pairing-plus-quadrupole model with monopole corrections is tested through detailed comparison between the calculation and experimental data. By using the experimental energy of the core-excited $21/{2}^{+}$ level in ${}^{131}$In as a benchmark, monopole corrections are determined that describe the size of the neutron $N=82$ shell gap. The level spectra, up to 5 MeV of excitation in ${}^{131}$In, ${}^{131}$Sn, ${}^{130}$In, ${}^{130}$Cd, and ${}^{130}$Sn, are well described and clearly explained by couplings of single-hole orbitals and by core excitations.