Medium-spin structure of neutron rich nuclei ${}^{92}\mathrm{Sr}$, ${}^{94}\mathrm{Sr}$, and ${}^{96}\mathrm{Sr}$ have been studied in spontaneous fission of ${}^{248}\mathrm{Cm}$. New spin and parity assignments done in this work differ significantly from those reported in other works. The $9^{-}$ excitations, involving the $\nu (g_{7/2}{h}_{11/2}){}_{9^{-}}$ maximum aligned configuration, were proposed in the three nuclei at 4930.2 keV, 4858.6 keV, and 3523.9 keV, respectively. Shell-model calculations, with the ${}^{78}\mathrm{Ni}$ core, support the proposed nature of the $9^{-}$ excitations. The new data allow testing the single-particle energies in the region of ${}^{78}\mathrm{Ni}$, and in particular, the position of the $\nu h_{11/2}$ orbital, which was not uniquely determined to date.

• Received 10 October 2008

DOI:https://doi.org/10.1103/PhysRevC.79.024319