High-spin states of the N=82 isotones Xe136, Cs137 , and Ba138 : Monopole-driven competition of neutron core excitations with two-proton excitations to the h11/2 high- j orbit

Dec 24, 2019
11 pages
Published in:
  • Phys.Rev.C 100 (2019) 6, 064316
  • Published: Dec 24, 2019

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20182019202001
Abstract: (APS)
It is known that the monopole effect in shell-model calculations can influence single-particle states dynamically, resulting in novel shell evolution near the ground state. We show that a monopole-driven competition between different excitation modes can occur in the high-lying, high-spin states in nuclei above Sn132. Stimulated by the recent high-spin data, we extend large-scale shell-model calculations with the effective interaction determined in our previous work [Phys. Rev. C 84, 044324 (2011)10.1103/PhysRevC.84.044324] to study the heavier N=82 isotones Xe136, Cs137, and Ba138. With inclusion of configurations for neutron core excitation across the N=82 shell gap, we treat simultaneously two kinds of excitation modes for the high-spin states, namely, those from multiproton coupling within the valence-proton space and from neutron core excitation to the upper orbits above the N=82 shell gap. Based on a good reproduction of the experimental data, we discuss the competition mechanism by analyzing the monopole effect in the effective single-particle energies.
  • Nuclear Structure