Ab initio calculation of the frequency-dependent interaction induced hyperpolarizability of Ar-2

The frequency-dependent interaction induced polarizability and second hyper polarizability of the argon dimer are computed for a range of internuclear distances employing the coupled cluster singles and doubles response approa ch. The frequency dependence of the interaction-induced properties is treat ed through second order in the frequency arguments using expansions in Cauc hy moments and hyperpolarizability dispersion coefficients. The dielectric, the refractivity, the Kerr and the hyperpolarizability second virial coeff icients are computed for a range of temperatures employing a recent accurat e ab initio potential for the ground state of the argon dimer. For most of the computed virial coefficients good agreement is obtained between the pre sent ab initio results and the available experimental data. (C) 1999 Americ an Institute of Physics. [S0021-9606(99)00306-2].