Decay of theKπ=8−isomer inHf182

The decay of 61.5-min ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hf}_{}^m{}_{}{}^{}(K^{\pi }=8^{-})$ in chemically separated and mass-separated sources has been studied by means of Ge(Li) detectors and a plastic scintillation detector. Twenty-eight $\gamma$ rays, and two $\beta$ rays of 480±50 and 970±70 keV, were assigned to the decay of ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hf}_{}^m{}_{}{}^{}$. The 480-keV $\beta$ group was observed to be in coincidence with high-energy $\gamma$ rays. Ge(Li)-Ge(Li) $\gamma -\gamma$ coincidence measurements established the $K^{\pi }=0^{+}$ ground state rotational band of ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hf}$ up to the $I=8\mathrm{}$ member. The energy of the isomeric state is at 1172.9 keV in ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hf}$. ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hf}_{}^m{}_{}{}^{}$ decays 54% by negatron emission to levels at 653, 1116, and 1337 keV in ${}_{}{}^{182}{}_{}{}^{}\mathrm{Ta}$. The 653- and 1116-keV levels are identified as $K^{\pi }=9^{-}\mathrm{and}{7}^{-}$ states, respectively, with possible Nilsson configurations of ${\frac{9}{2}}^{-}{\mathrm{}\left[514\right]\mathrm{}}_p$, ${\frac{9}{2}}^{+}{\mathrm{}\left[624\right]\mathrm{}}_n$, and ${\frac{7}{2}}^{+}{\mathrm{}\left[404\right]\mathrm{}}_p$, ${\frac{7}{2}}^{-}{\mathrm{}\left[514\right]\mathrm{}}_n$. The $Q$ value for $\beta$ decay of ${}_{}{}^{182}{}_{}{}^{}\mathrm{Hf}$ has been inferred to be 432±41 keV.