Experimental evidence for coexisting structures in125I

Abstract

Properties of the collective bands in ${}^{125}\mathrm{I},$ populated in ${}^{123}\mathrm{Sb}(\ensuremath{\alpha},2n\ensuremath{\gamma}{)}^{125}\mathrm{I}$ reaction at $E=30 \mathrm{MeV},$ have been studied from $\ensuremath{\gamma}$-ray angular distributions and excitation functions. Spins and parities are inferred for several states. New $E2/M1$ mixing ratios are deduced for five transitions. A three-quasiparticle collective band is proposed on the basis of these and earlier results. The shapes of the ground state yrast band and the ${g}_{9/2}$ band are discussed, providing evidence for the coexistence of prolate and oblate collective states.