Yrast structure of the shell model nucleusNb89

Abstract

Yrast and near-yrast states in $\text{odd-}A$ $^{89}\mathrm{Nb}$ were investigated using the $^{65}\mathrm{Cu}(^{28}\mathrm{Si}$,$2p2n)$ reaction at a beam energy of 105 MeV. The $\ensuremath{\gamma}\text{-ray}$ coincidence events were recorded with the Indian National Gamma Array spectrometer. About 30 new transitions have been observed extending the level structure of this nucleus up to spin $45/2\ensuremath{\hbar}$ and excitation energy of 10.5 MeV. Large-scale shell model calculations were performed using the effective interactions JUN45 and jj44b to understand the structure of the observed states. Reasonable agreement between the experimental observation and shell model calculations suggests that no cross-shell excitations are important up to the maximum spin observed in the current experiment.