Low-lying structure and weak-coupling multiplets of odd-mass Te isotopes below and beyond the neutron magic number N=82

Abstract

The low-lying level schemes, $E2$ transitional rates, electrical quadrupole moments $Q$, and magnetic dipole moments $\mu$ of odd-mass Te isotopes with mass number from 129–139 are calculated within the framework of the nucleon-pair approximation of the shell model by using the standard multipole-multipole interaction in a large truncated space. Good agreement is obtained between the calculated results and experimental data. The dominant configurations in collective nucleon-pair basis of low-lying yrast states in ${}^{129–133}\mathrm{Te}$ and ${}^{135–139}\mathrm{Te}$ are analyzed in detail. The possible weak-coupling multiplets in these nuclei are probed by investigating the corresponding relative excitation energy, wave function, $E2$ transition rates, electric quadrupole moments $Q$, and magnetic dipole moment $\mu$. $E2$ ground-state transitions of odd-mass nuclei and even-even core are compared, and a similar asymmetry pattern with respect to $N=82$ is obtained. The electromagnetic moments $Q$ and $\mu$ of the $3/2_1^{+}, 11/2_1^{-}$ states in ${}^{129–133}\mathrm{Te}$, and the $7/2_1^{-}$ state in ${}^{135–139}\mathrm{Te}$ are discussed in terms of the overall trend and the contribution of the proton and neutron components.