Large-scale shell- model study for excitations across the neutron N=82 shell gap in Sb131-133

作者：Wang, Han-Kui^*; Ghorui, S. K.; Kaneko, Kazunari; Sun, Yang^*; Li, Z. H.

来源：PHYSICAL REVIEW C, 2017, 96(5): 054313.

DOI：10.1103/PhysRevC.96.054313

• PROTON-NUCLEUS SB-133
• PARTICLE STATES
• SN-132
• ISOMER
• SPIN

The cross-shell excitations in the mass-130 region are determined by the behavior of the single-particle (or single-hole) states around the doubly magic nucleus Sn-132 and the size of the energy gaps at N = 82 and/or Z = 50. The present work reports on the results from large-scale shell-model calculations with the extended paring plus quadrupole-quadrupole force, usually with additions of monopole corrections (the EPQQM model). This paper applies the EPQQM model to the northwestern quadrant of Sn-132. The model space includes the orbits of (0(g7/2),1d(5/2),1d(3/2),2s(1/2),0h(11/2)) for both protons and neutrons, with two additional neutron orbits (1 f(7/2),2p(3/2)) above the N = 82 shell gap, allowing cross-shell excitations. It is found that the experimentally known low-lying levels for Sb-133, Sb-132, and Sb-131 can be well described. The highly excited states above 4.0 MeV are clearly explained as excitations across the neutron N = 82 shell gap. The monopole effects in these nuclei are carefully examined. In contrast to the already studied northeastern and southwestern quadrants around Sn-132 by the EPQQM model, the description of the current Sb data does not request particular monopole corrections. Experiments to further explore the cross-shell excitations in the Sb isotopes are called for.

• 出版日期2017-11-15
• 单位周口师范学院; 中国原子能科学研究院; 中国科学院近代物理研究所; 上海交通大学