States inAg105,107populated by heavy-ion reactions and interpreted by a quasiparticle-plus-rotor model

Levels in ${}_{}{}^{105,107}{}_{}{}^{}\mathrm{Ag}$ have been studied using heavy-ion reactions. The experiments included $\gamma$-ray yields as a function of bombarding energy, $\gamma$-ray angular distributions, and three-detector $\gamma -\gamma$ coincidence measurements. The positive-parity band based on the unique-parity $g_{\frac{9}{2}}$ orbital in both nuclei exhibits a $\Delta I=1\mathrm{}$ character, unlike its counterpart $h_{\frac{11}{2}}$ band in Pd nuclei. The energy levels, $\gamma$-ray mixing ratios, branching ratios, and lifetimes in this band as well as in the ground-state negative-parity band are shown to be in good agreement with calculations using a particle-plus-rotor model at a small, symmetric deformation ($\delta =0.12\mathrm{}$). The Coriolis and recoil effects are explicitly included and a variable moment of inertia is used. The low-lying "anomalous" $\frac{7}{2^{+}}$ state is also readily reproduced by this model. The calculation also shows that the $\Delta I=1\mathrm{}$ nature of the positive-parity band results primarily from the fact that the Fermi surface is far from the $K=\frac{1}{2}$ state, whereas the transition properties are governed by the Coriolis mixing of the strong-coupled bands. Two bands built on the $\frac{17}{2^{-}}$ and $\frac{21}{2^{+}}$ states with high bandhead energies are thought to have three-quasiparticle configurations.