The non-empirical calculation of second order molecular properties by means of effective states

Publisher Website
Google Scholar
Abstract
A method is presented for the efficient calculation of second order (multipole) properties. A complete spectrum (including the continuum) is represented by a small number of effective states. Relations with several existing techniques, such as Padé approximants and generalized Gaussian quadratures, are discussed. The method is applied to time-dependent Hartree-Fock calculations of dynamic multipole polarizabilities and dispersion interactions. For He, Ne, H2 and N2 effective spectra are presented which yield dispersion coefficients for the ten possible Van der Waals dimers within 1·2, 3·9 and 6·4 per cent of the full TDCHF C 6, C 8 and C 10-coefficients, respectively. These effective spectra are useful if knowledge of Van der Waals surfaces and dynamic polarizabilities is required to interpret experimental data.