Measurement of the Electric Dipole Polarizabilities of Metastable Mercury

The electric dipole polarizabilities of the $6s6p {}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ metastable state of mercury have been measured, using the $E-H$ gradient-balance technique. The values obtained are ${\alpha }_{\mathrm{zz}}(M_J=2)=(4.7\mathrm{}\pm 1.9)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^3$, ${\alpha }_{\mathrm{zz}}(M_J=1)=(4.4\mathrm{}\pm 0.9)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^3$, and $\overline{\alpha }=(4.5\mathrm{}\pm 1.5)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^3$. In addition, the average polarizability of the $5d^{9}6s^{2}6p {}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}$ metastable state of mercury has been measured, using an electric-deflection method. For this state, $\overline{\alpha }=(1.8\mathrm{}\pm 0.8)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^3$. The metastable atoms are produced by electron bombardment of a ground-state mercury beam, and are detected by Auger ejection of electrons from a cesium-coated tungsten surface. The data are interpreted by simulating the experimental conditions on a digital computer.