Quadrupole Moment of the 660-keV "Rotational" Level ofIn117

The quadrupole interaction frequency ${\nu }_Q=\frac{e^2\mathrm{qQ}}{h}$ of the 660-keV ($I={\frac{3}{2}}^{+}$) level of ${}_{}{}^{117}{}_{}{}^{}\mathrm{In}$ has been measured by the method of time-differential perturbed angular correlations in an alloy of ${\mathrm{In}}_{0.99}$ ${\mathrm{Cd}}_{0.01}$ at 4.2°K. From the known quadrupole interaction of ${}_{}{}^{115}{}_{}{}^{}\mathrm{In}$ in the same alloy at 4.2°K and the atomic beam value of $Q\left({}_{}{}^{115}{}_{}{}^{}\mathrm{In}\right)$, the quadrupole moment of this level is deduced to be $\mathrm{}\left|Q\right|=0.64\mathrm{}\left(4\right)\mathrm{}$ b, in remarkable agreement with the theoretical value of 0.636 b derived from a description of this level as a rotational state of a $K={\frac{1}{2}}^{+}$ band.