High-spin states of isotonic ${}_{}{}^{96}{}_{}{}^{}\mathrm{Rh}$ and ${}_{}{}^{97}{}_{}{}^{}\mathrm{Pd}$ were studied by means of the ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$${(}^{40}$Ca, α3pnγ${)}^{96}$Rh and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$${(}^{40}$Ca, α2pnγ${)}^{97}$Pd reactions, respectively, with ${\mathit{E}}_{\mathit{l}\mathit{a}\mathit{b}}$=167 MeV. Levels up to 5.5 MeV with ${\mathit{J}}^{\mathrm{\pi }}$=${15}^{+}$ in ${}_{}{}^{96}{}_{}{}^{}\mathrm{Rh}$ were populated while levels in ${}_{}{}^{97}{}_{}{}^{}\mathrm{Pd}$ up to 7.5 MeV were found. The yrast (21/$2^{+}$ level of ${}_{}{}^{97}{}_{}{}^{}\mathrm{Pd}$ was found to decay to a (19/$2^{+}$ level, in contrast to the behavior of the lighter odd-A isotones. An attempt to measure lifetimes using a neutron-γ coincidence technique revealed no new isomers in either nuclide with ${\mathit{t}}_{1/2}$≥5 ns. The discovery of two low-lying transitions of 125 keV in ${}_{}{}^{96}{}_{}{}^{}\mathrm{Rh}$ requires a slight revision of a recently reported value of its atomic mass as well as that of isobaric ${}_{}{}^{96}{}_{}{}^{}\mathrm{Pd}$. The high-spin structure and the N=51 systematics, particularly the location of the ν${\mathit{g}}_{7/2}$ strength, are compared with the results of shell-model calculations.

• Received 10 October 1989

DOI:https://doi.org/10.1103/PhysRevC.41.1223