MOLECULAR INTERACTION POTENTIAL - A NEW TOOL FOR THE THEORETICAL-STUDY OF MOLECULAR REACTIVITY

A new methodology to compute molecular interaction potentials (MIPs) is developed and tested. The calculation of the MIP is based upon the generalization of the rigorous quantum mechanical molecular electrostatic potential (MEP) and further addition of a classical repulsion-dispersion term. As a result, the MIP is able to represent not only with high accuracy electrostatic interactions but also represent in a suitable way steric effects. The analysis of the results obtained for different molecules demonstrates the superiority of the MIP with regard to the standard MEP to describe nonbonded interactions, in particular hydrogen bonds. The comparison of results calculated at the ab initio I6-31G* and semiempirical AM1 levels points out the suitability of semiempirical calculations to qualitatively reproduce the most relevant reactive features of the molecules. Finally, possible applications of the MIP in different fields are discussed.