Directional Correlations and Electric Quadrupole Moments of Mercury Isotopes

The directional correlation of the 368-kev and the 159-kev $\gamma$ rays of 44-min ${\mathrm{Hg}}^{199}$ were studied with sources in the form of liquid metal, frozen metal, and dry crystalline Hg${\mathrm{Cl}}_2$. The results in the liquid metal, if free of scattering and of disturbances in the intermediate state, indicate a mixing of 0.8% $E5\mathrm{}$ with the predominantly $M4\mathrm{}$ first $\gamma$ ray, assuming the second to be pure $E2\mathrm{}$. The disturbance observed in the frozen metal suggests a static electric quadrupole interaction $\frac{eQ\left(\frac{{\partial }^{2}V}{\partial z^2}\right)}{h}$ of 593 Mc/sec whereas that in Hg${\mathrm{Cl}}_2$ suggests similar interaction of 1100 Mc/sec for the 2.35-mμsec intermediate state. If the second $\gamma$ ray is a rotational transition, an intrinsic quadrupole moment determined from the intermediate lifetime can be used together with these values and the coupling observed for ${\mathrm{Hg}}^{201}$ in Hg${\mathrm{Cl}}_2$ to compute the electric quadrupole moment of ${\mathrm{Hg}}^{201}$. The resulting value of ${0.46}_{-0.11\mathrm{}}^{+0.28\mathrm{}}$ barn is in excellent agreement with the spectroscopically determined value of 0.45±0.04 obtained by Murakawa.