Dynamic multipole polarizabilities, reduced spectra, and interaction coefficients for N2 and CO

Abstract

Reliable ab initio reduced spectra that serve to calculate dynamic polarizabilities as well as long-range interaction coefficients are presented. The reduced spectra are constructed from perturbed functions that are computed in the single excitation multi-reference averaged coupled pair approach. The static dipole polarizabilities are of the same quality as values obtained in a recent study using elaborated coupled cluster expansions. The dynamic dipole polarizabilities are in excellent agreement with all experimental data available. The higher multipole polarizabilities (l⩽3) are also expected to be the most reliable ones up to date. The interaction coefficients for the N2–N2 interaction perfectly match the coefficients obtained from semiempirical anisotropic oscillator strength distributions. For the CO–CO interaction, however, the same quantities differ by up to 10%. We believe our coefficients to be accurate to 3%.