Dipole Polarizability, Cauchy Moments, and Related Properties of Hg

We report interferometric measurements of the frequency dependence of the refractive index n and the dipole polarizability α of Hg vapor. From the measured dispersion of the dipole polarizability the Cauchy moments S (−2) = 33.91(34), S (−4) = 279.8(8.4), and S (−6) = 14 100(2810) have been obtained. The static limit S (−2) is in good accordance with ab initio calculations and results obtained from dielectric constant measurements. The Cauchy moments are used to predict approximations of the dispersion interaction energy constant C 6 = 255 au and the second hyperpolarizability γ(0) = 2.2 × 10 4 au.