Search for closed-shell effects on theE2M1mixing of transitions inSn116

Directional-correlation measurements of several cascades in ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ have been made with a NaI-Ge(Li) detector system. Of particular interest in the 819-keV, $2^{+\prime }$ → $2^{+}$ transition which was classified earlier as 90% $E2\mathrm{}$ and almost pure $M1\mathrm{}$ by two different groups. The $\gamma -\gamma \left(\theta \right)$ measurements of the $2^{+\prime }$(819-keV) → $2^{+}$ (1293-keV) → $0^{+}$ cascade yield $A_2$ and $A_4$ coefficients of 0.31(2) and 0.27(5), respectively. From these data a $\delta \left(\frac{E2\mathrm{}}{M1\mathrm{}}\right)$ of $-1.8\mathrm{}\left(2\right)\mathrm{}$ is obtained for the 819-keV transition, which corresponds to 76.4 ± 3.7% $E2\mathrm{}$ radiation. The $\gamma$- ray intensities were measured more precisely.