The $\gamma$-ray spectrum of the decay of ${}_{}{}^{158}{}_{}{}^{}\mathrm{Ho}$ in transient equilibrium with 2.3-h ${}_{}{}^{158}{}_{}{}^{}\mathrm{Er}$ has been studied with Ge(Li) detectors. Results of $\gamma$-ray singles and coincidence experiments are reported and a decay scheme for ${}_{}{}^{158}{}_{}{}^{}\mathrm{Ho}$ → ${}_{}{}^{158}{}_{}{}^{}\mathrm{Dy}$ is proposed. New levels have been assigned to the $\beta$-vibrational band and a rotational band built on the two-quasineutron state ($\nu \frac{5}{2^{-}}\mathrm{}\left[523\right]+\nu \frac{3}{2^{-}}\mathrm{}\left[521\right]\mathrm{}$). A new $K=2\mathrm{}$ rotational band with spins up to $6^{+}$ built on a level at 1851.9 keV is proposed. An attempt is made to characterize a group of negative parity states at about 1400 keV, and tentative assignments of the $K=0, 1, \mathrm{and} 2$ octupole vibrational band heads are suggested.

RADIOACTIVITY ${}_{}{}^{158}{}_{}{}^{}\mathrm{Ho}$ [from ${}_{}{}^{148}{}_{}{}^{}\mathrm{Nd}({}_{}{}^{14}{}_{}{}^{}\mathrm{N}, 4n)$; ${}_{}{}^{150}{}_{}{}^{}\mathrm{Sm}({}_{}{}^{12}{}_{}{}^{}\mathrm{C}, 4n)$, ${}_{}{}^{151}{}_{}{}^{}\mathrm{Eu}({}_{}{}^{11}{}_{}{}^{}\mathrm{B}, 4n)$ $(2.3-\mathrm{h}, \mathrm{EC}, {\beta }^{+}){}_{}{}^{158}{}_{}{}^{}\mathrm{Ho}$]; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$ coin, $T_{\frac{1}{2}}$, deduced $log\mathrm{ft}$, ${}_{}{}^{158}{}_{}{}^{}\mathrm{Dy}$ deduced levels, $J$, $\pi$, ${\alpha }_K$, $\gamma$ multipolarities. Ge(Li) detectors.

• Received 30 September 1974

DOI:https://doi.org/10.1103/PhysRevC.11.974