Band structures in doubly oddRh98

Abstract

Excited states in the transitional doubly odd $^{98}\mathrm{Rh}$ nucleus were populated in the $^{75}\mathrm{As}$($^{28}\mathrm{Si}$,2$p$3$n$) fusion-evaporation reaction using the 120-MeV incident $^{28}\mathrm{Si}$ beam. The subsequent de-excitations were investigated through in-beam $\ensuremath{\gamma}$-ray spectroscopic techniques using an early implementation phase of the Indian National Gamma Array (INGA) spectrometer equipped with 18 clover Ge detectors. The level structures in $^{98}\mathrm{Rh}$ have been established up to excitation energy $\ensuremath{\approx}$10 MeV and angular momentum $\ensuremath{\sim}$23$\ensuremath{\hbar}$. The previously reported level schemes are considerably modified and extended substantially. Significant expansion of the level scheme at low excitation energies stipulates that the previously reported 842-726-994-980-265 keV $\ensuremath{\gamma}$-transition cascade in $^{98}\mathrm{Rh}$ is not directly based on the ground state (T${}_{1/2}$ = 8.7 min). Tilted-axis cranking (TAC) shell-model calculations have been used to put the present level scheme of $^{98}\mathrm{Rh}$ in perspective. Level structures have been interpreted in terms of the rotational bands based on the $\ensuremath{\pi}{p}_{1/2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}$ [triaxiality parameter ($\ensuremath{\gamma}$) = 25${}^{\ensuremath{\circ}}$], and $\ensuremath{\pi}{f}_{5/2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}$ proton-neutron configurations having moderate quadrupole deformation (${\ensuremath{\epsilon}}_{2}$ $\ensuremath{\approx}$ 0.13) and the admixtures. Excited band structures are based on the $\ensuremath{\pi}{p}_{1/2}/{f}_{5/2}\ensuremath{\bigotimes}\ensuremath{\pi}$(${g}_{9/2}$)${}^{2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}$ configuration and the fully stretched [$\ensuremath{\pi}{p}_{1/2}\ensuremath{\bigotimes}\ensuremath{\nu}$(${h}_{11/2}$)${}^{2}\ensuremath{\bigotimes}\ensuremath{\nu}{d}_{5/2}$]${}_{{13}^{\ensuremath{-}}}$ configuration.