The use of the point charge model in the evaluation of spectral shifts within the INDO/CIS approximation

Abstract

The point charge model incorporated into the intermediate neglect of differential overlap–configuration interaction singles scheme (INDO/CIS) has been used to calculate spectral shifts in aromatic systems due to intermolecular interactions. The arrangement of the solvent molecules around the central molecule was obtained using the simulated annealing method based on a classical potential energy surface. This method of evaluating the spectral shifts, using the same values for the point charges as used in the solute–solvent simulation where the solute is in its ground state, has been shown to be unreliable when applied to simple Van der Waals systems.