Minimal basis sets in calculations of intermolecular interaction energies

Abstract

Several minimal (7, 3/3) Gaussian basis sets have been used to calculate the energies and some other properties of CH4 and H2O. Improved basis sets developed for these molecules have been extended to NH3 and HF and employed to H2CO and CH3OH. Interaction energies between XHn molecules have been calculated using the old and the new minimal basis sets. The results obtained with the new basis sets are comparable in accuracy to those calculated with significantly more extended basis sets involving polarization functions. Binding energies calculated using the counterpoise method are not much different for the new and the old minimal basis sets, and are likely to be more accurate than the results of much more extended calculations.