CO2–N2 intermolecular V–T and V–V potentials via CNDO

Abstract

V–T and V–V intermolecular potentials have been calculated within the CNDO approximation for the CO2 (asymmetric mode) –N2 system. The procedure followed was to compute the total energy of the CO2–N2 system for a variety of intermolecular separations, orientations, and normal mode displacements, and subtract the relevant isolated CO2 and isolated N2 total energies. The V–T and V–V intermolecular potentials were then obtained by fitting a second-order polynomial expansion in the normal mode displacements of both molecules to the total intermolecular energy for each intermolecular orientation and displacement. The resulting elastic potentials are much too deep. The inelastic potentials are highly orientation dependent, generally not well represented by a P2(ϑ) expansion in the relative angular orientation, and different for each specific V–T or V–V process.