DISPERSION DIPOLES, QUADRUPOLES AND ELECTRIC-FIELD GRADIENTS

Dispersion dipoles, quadrupoles and electric-field gradients at nuclei can be represented as integrals of frequency-dependent monomer polarisabilities and hyperpolarisabilities and are therefore accessible in ab initio calculations that combine finite-field and analytic methods. Static approximations lead to a physical interpretation of the size and sign of the induced properties calculatedfrom the exact formula. A coupled-Hartree-Fock implementation is described and results are presented for pairs involving H, He, Ne, Ar and CH4. © 1990.