The ${}^{88}$Kr nucleus has been reinvestigated with prompt-$\gamma$-ray-spectroscopy methods using the Gammasphere Ge array to measure $\gamma$ rays following spontaneous fission of ${}^{252}$Cf. The order of some of the transitions, reported previously, has been changed and new levels were introduced. Angular correlation analysis allowed the assignment of spins to several levels in ${}^{88}$Kr. These data, together with the shell-model calculations, explained the near-yrast structure of ${}^{88}$Kr, which is similar to the structure of the $N=52$, ${}^{90}$Sr, and ${}^{92}$Zr isotones. The regular systematics obtained for the three isotones suggests that the spin of the 2073.4-keV level in the ${}^{86}$Se isotone is different from the $I=6$ value reported previously. Using data from prompt $\gamma$-ray measurement of spontaneous fission of ${}^{248}$Cm, we reinvestigated the ${}^{86}$Se nucleus. A new candidate for the 6${}_1^{+}$ level in ${}^{86}$Se has been proposed, which is supported by shell-model calculations. Energies of the 2${}_1^{+}$ and 4${}_1^{+}$ levels in the ${}^{82}$Zn nucleus have been predicted using a novel systematics.

• Received 3 April 2013

DOI:https://doi.org/10.1103/PhysRevC.88.044314