Isomerism and persistence of the N=82 shell closure in the neutron-rich 132Sn region

The occurrence of seniority isomers in semimagic nuclei is a clear indication for shell closure. By performing large-scale shell-model calculations in a model space that allows excitations across the N = 82 neutron and Z = 50 proton shell gaps, we investigate the isomerism along the N = 82 isotonic chain. The calculation describes well the properties of the experimentally observed 8(+) isomeric state and the other low-lying states in Pd-126, Pd-128, and Cd-130. We further predict energy levels and E2 transitions for Ru-126 and Mo-124 as their structure information is necessary for a complete understanding of the seniority picture. Our results, together with other existing evidence, support the conclusion that the shell closure persists at the neutron number N = 82 in the neutron-rich region.