PAIR POLARIZABILITY OF HYDROGEN ATOMS . RELATION TO COLLISION-INDUCED LIGHT SCATTERING AND DIELECTRIC PHENOMENA IN RARE GASES

The polarizability tensor as a function of internuclear separation of hydrogen atoms is calculated, using the approximate variational wavefunction for ground- and first-excited-state Hi of Hirschfelder and Linnett. Two interacting hydrogen atoms in the nonbonding triplet state have certain qualitative features in common with colliding pairs of rare-gas atoms. In particular, the system exhibits the long-range dispersion attraction and short-range overlap repulsion of interacting closed shell atoms. Results of the calculations here on 3∑H2 are capable, in analogy, of explaining observed trends in collision-induced light scattering intensities and the second dielectric virial coefficient of rare gases, which cannot be accounted for on the basis of longrange dispersion force models or perturbation theory alone. The major source of the effect is found to be the distortion of electronic charge density at intermediate and small internuclear separations.