Time-dependent directional correlations ofHgm199in liquid Hg, solid Hg, and HgCl2

Time-directional correlations of the 374- and 158-keV $\gamma$ rays of ${}_{}{}^{199}{}_{}{}^{}\mathrm{Hg}_{}^m{}_{}{}^{}$ were studied with sources in the form of liquid Hg, frozen Hg, and dry crystalline Hg${\mathrm{Cl}}_2$. The time-dependent anisotropy in the liquid at room temperature shows no observable disturbance over several lifetimes. The integral anisotropy in the liquid indicates mixing of $E5\mathrm{}$ with the predominantly $M4\mathrm{}$ first $\gamma$ ray with an $\frac{M4\mathrm{}}{E5\mathrm{}}$ mixing ratio $\delta =0.092\mathrm{}\pm 0.015$. The half-life of the intermediate state was determined to be 2.47 ± 0.05 nsec. Time-dependent directional correlations in frozen emulsified Hg show a quadrupole interaction $\frac{eQ\left(\frac{{\partial }^{2}V}{\partial z^2}\right)}{h}=198\mathrm{}\pm 40$ MHz. The time-dependent coincidence rate in Hg${\mathrm{Cl}}_2$ shows a quadrupole interaction $\frac{eQ\left(\frac{{\partial }^{2}V}{\partial z^2}\right)}{h}=1271\mathrm{}\pm 30$ MHz. If the second $\gamma$ ray is a rotational transition, the quadrupole moment of the intermediate state determined from the intermediate-state $E2\mathrm{}$ lifetime can be combined with the nuclear-quadrupole-resonance frequency of ${}_{}{}^{201}{}_{}{}^{}\mathrm{Hg}$ in Hg${\mathrm{Cl}}_2$ to give a quadrupole moment for ${}_{}{}^{201}{}_{}{}^{}\mathrm{Hg}$ of 0.39 ± 0.02 b. This result is in excellent agreement with the value of 0.41 b obtained by Murakawa from the hyperfine structure of atomic mercury.