Gamma-ray cascades in the two- and three-valence-particle nuclei ${}^{134}\mathrm{Sb}$ and ${}^{135}\mathrm{Te}$ have been studied with Gammasphere using a ${}^{248}\mathrm{Cm}$ spontaneous fission source. Isotopic assignments were based in part on coincidences with γ rays from complementary Rh and Ru fission partners. The ${}^{134}\mathrm{Sb}$ and ${}^{135}\mathrm{Te}$ level schemes have been considerably extended, with placement of many new high-energy γ rays; delayed γ-ray coincidences observed across a 0.51-μs yrast isomer in ${}^{135}\mathrm{Te}$ were especially fruitful. The yrast level spectra of both nuclei are interpreted using empirical nucleon-nucleon interactions and compared with the known yrast excitations of their counterparts ${}^{210}\mathrm{Bi}$ and ${}^{211}\mathrm{Po}.$

• Received 16 October 2000

DOI:https://doi.org/10.1103/PhysRevC.63.024322