A model for multipole polarizabilities and dispersion coefficients

Abstract

Multipole polarizabilities and dispersion coefficients for molecules X Y_n , (n = 2 to 6) can be defined in terms of two bond polarizability parameters and a distance. Coupled Hartree-Fock (CHF) calculations of α, A, E and C polarizability of CO₂, BeH₂, BF₃, NO₃ ⁻, CH₄, ClF₄ ⁻, PF₅ and SF₆ are presented and the results compared with the predictions of the anisotropic bond polarizability model. The model is found to give a useful qualitative picture of these higher tensor properties, giving signs and relative magnitudes of components. Absolute magnitudes are erratically represented in the model if no adjustment of parameters is allowed. A consistent extension to dispersion coefficients is outlined, and sample predictions are compared with CHF results for Ar-CO₂ and Ar-SF₆.