We have verified that a 493.7-, 911.0-, 879.5-, 648.9-, 805.2-, 264.0-keV $\gamma$-ray cascade, produced by both ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$+${}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}$, occurs in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Pd}$ by the observation both of coincidences between these $\gamma$ rays and palladium $K$ x rays and of $\gamma$-ray excitation functions. Moreover, this cascade is found to be preceded by a (33.72±0.05)-keV transition. A second $\gamma$-ray cascade with side chains also resulting from these bombardments is in addition produced by ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$+${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$. Therefore, this second cascade must occur in a nuclide with $Z\le 45$ and not in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Pd}$, as has been proposed by other investigators. Arguments are given in favor of the conjecture that this second $\gamma$-ray cascade populates the 4.7-h isomeric state of ${}_{}{}^{99}{}_{}{}^{}\mathrm{Rh}$.

NUCLEAR REACTIONS ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$+${}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}$, $E=110-140\mathrm{}$ MeV; measured $\gamma -\gamma$ coin, $\gamma$-x ray coin, ${\sigma }_{\mathrm{rcl}}\mathrm{}\left(E\right)\mathrm{}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$, $E=56-66\mathrm{}$ MeV; measured ${\sigma }_{\mathrm{rcl}}\mathrm{}\left(E\right)\mathrm{}$, $W\left(t_{\gamma }\right)$ by pulsed beam; ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$+${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$, $E=40-55\mathrm{}$ MeV; measured ${\sigma }_{\mathrm{rel}}\mathrm{}\left(E\right)\mathrm{}$; ${}_{}{}^{99}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{99}{}_{}{}^{}\mathrm{Rh}$ deduced levels, $J^{\pi }$; enriched targets, Ge(Li), Si(Li) detectors.

• Received 11 August 1976

DOI:https://doi.org/10.1103/PhysRevC.15.287