Beta decay ofRb75to low-lying levels inKr75

The isotope ${}_{}{}^{75}{}_{}{}^{}\mathrm{Rb}$ was produced via the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$(${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, p2n) reaction and mass separated with an on-line isotope separator. Its half-life was determined to be 21.4 ± 1.0 sec. Twenty-one $\gamma$ rays were placed in a partial decay scheme with levels in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Kr}$ up to 1042.4 keV in excitation. The data are consistent with the existence of previously proposed ${\frac{5}{2}}^{+}$ ground-state and ${\frac{3}{2}}^{-}$ first-excited-state rotational bands in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Kr}$, and with a ${\frac{3}{2}}^{-}$ or ${\frac{5}{2}}^{-}$ assignment for the ground state of ${}_{}{}^{75}{}_{}{}^{}\mathrm{Rb}$.