THE APPLICATION OF LOCALIZED REPRESENTATION IN THE CALCULATION OF INTERACTION ENERGY

The results presented in this paper for the dimer of H2O as well as fo r the dative complexes formed by the interaction of BH3 + H2O and AlH3 + H2O suggest that about 50% of the dispersion energy can be recovere d, using a 6-31G(d) basis set, in cases when only the contributions of those localized molecular orbitals are included which are in the vici nity of the interaction region. The reduction in computing time is abo ut an order of magnitude. The procedure applied makes it possible to a void basis set superposition errors at the correlated level. The metho d presented opens the way for studying large clusters containing vario us atoms beyond the HF level.