We have investigated the decay of ${}_{}{}^{85}{}_{}{}^{}\mathrm{Kr}_{}^m{}_{}{}^{}$, ${}_{}{}^{85}{}_{}{}^{}\mathrm{Kr}_{}^g{}_{}{}^{}$, ${}_{}{}^{85}{}_{}{}^{}\mathrm{Sr}_{}^m{}_{}{}^{}$, and ${}_{}{}^{85}{}_{}{}^{}\mathrm{Sr}_{}^g{}_{}{}^{}$ using Ge(Li) spectroscopy and intrinsic Ge Compton-suppression spectroscopy techniques. We observe levels at ($J^{\pi }$ in parentheses) g.s. ($\frac{5}{2^{-}}$), 151.18 ($\frac{3}{2^{-}}$), 281.01 ($\frac{1}{2^{-}}$), 513.998 ($\frac{9}{2^{+}}$), 731.79 ($\frac{3}{2^{-}}$), 868.05 ($\frac{7}{2^{-}}$), and 921 ($\frac{1}{2^{-}}$,$\frac{3}{2^{-}}$) KeV. Our data suggest that the ∼880 keV level observed in ($t$,$\alpha$) and (${}_{}{}^3{}_{}{}^{}\mathrm{He}$,$d$) reactions is the known 868-keV level. The $Q_{\mathrm{EC}}$ value for the ${}_{}{}^{85}{}_{}{}^{}\mathrm{Sr}_{}^m{}_{}{}^{}$ decay is calculated to be 1323±20 keV from our $\frac{\mathrm{EC}}{{\beta }^{+}}$ intensity data. We use the cluster-vibration model to calculate the ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$ level structure and electromagnetic decay properties. For the latter, we discuss the role of the $M1\mathrm{}$ tensor operator.

NUCLEAR STRUCTURE Cluster-vibration model, influence of $M1\mathrm{}$ tensor term.

RADIOACTIVITY ${}_{}{}^{85}{}_{}{}^{}\mathrm{Kr}$, ${}_{}{}^{85}{}_{}{}^{}\mathrm{Kr}_{}^m{}_{}{}^{}$, ${}_{}{}^{85}{}_{}{}^{}\mathrm{Sr}$, and ${}_{}{}^{85}{}_{}{}^{}\mathrm{Sr}_{}^m{}_{}{}^{}$. Measured $E_{\beta }$,$I_{\beta }$. ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$ deduced levels, $E_{\beta }$, $I_{\beta }$, $J$,$\pi$. Ge(Li) detector, Compton-suppression spectrometer.

• Received 30 October 1978

DOI:https://doi.org/10.1103/PhysRevC.21.2590