γ-ray decays depopulating isomeric states have been observed in a number of very neutron deficient nuclei around $A\sim 80$ following the projectile fragmentation of a ${}^{92}\mathrm{Mo}$ primary beam. Previously unobserved decays have been identified in the $N=Z+2\mathrm{}$ nuclei ${}_{39}^{80}\mathrm{Y}$ and ${}_{41}^{84}\mathrm{Nb}$ and the $N=Z$ nucleus, ${}_{43}^{86}\mathrm{Tc},$ making the latter the heaviest $N=Z$ nucleus to date in which a discrete γ-ray transition has been assigned. The lifetime of the previously reported $I^{\pi }={\frac{9}{2}}^{+}$ isomeric state in ${}^{73}\mathrm{Kr}$ has also been measured and a clearer picture of its decay properties has been deduced. Isomeric ratios have been measured and have been interpreted in terms of the yrast or nonyrast nature of the isomeric state.

• Received 13 August 1999

DOI:https://doi.org/10.1103/PhysRevC.61.044309