(h11/2,g7/2)9−neutron excitation inSr92,94,96

Abstract

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 ${9}^{\ensuremath{-}}$ excitations, involving the $\ensuremath{\nu}({g}_{7/2}{h}_{11/2}){}_{{9}^{\ensuremath{-}}}$ 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 ${9}^{\ensuremath{-}}$ excitations. The new data allow testing the single-particle energies in the region of $^{78}\mathrm{Ni}$, and in particular, the position of the $\ensuremath{\nu}{h}_{11/2}$ orbital, which was not uniquely determined to date.