Nuclear structure of Te130 from inelastic neutron scattering and shell model analysis

Abstract

Excited levels of $^{130}\mathrm{Te}$ were studied with the $(n,$ ${n}^{\ensuremath{'}}\ensuremath{\gamma})$ reaction. Excitation functions, $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidences, angular distributions, and Doppler shifts were measured for $\ensuremath{\gamma}$ rays from levels up to an excitation energy of 3.3 MeV. Detailed information that includes level lifetimes, multipole-mixing ratios, branching ratios, and electromagnetic transition rates deduced from these measurements is presented. Large-scale shell model calculations performed with all proton and neutron orbitals in the 50--82 shell are compared to these data, with generally good agreement, particularly for the positive-parity states. To investigate emerging collectivity in $^{130}\mathrm{Te}$, the Kumar-Cline sum rules were used to evaluate rotational invariants from the shell model calculations. Whereas the ground state and first-excited state show the greatest average deformation, as expected, all of the low-lying states are weakly deformed and triaxial.