Polarisabilities and dispersion coefficients from the weighted exchange-hole model

Abstract

Frequency-dependent polarisabilities and dispersion coefficients are calculated for the molecules HF, CO, H2O and NH3 using the recently developed weighted exchange-hole (WXhole) model of the response function. The results are compared to those obtained by time-dependent Hartree–Fock and density functional theory (DFT) calculations. It is shown that the WXhole model yields response properties that can describe both, the isotropic and anisotropic contributions to the polarisabilty and dispersion coefficients with a reasonable accuracy. This result is notable taking into account the fact that the WXhole method is much less expensive than corresponding fully coupled Hartree–Fock and DFT methods and also, as is shown in this work, requires smaller basis sets to obtain converged results.