Investigation on the intermolecular electrostatic interactions of some polar molecules with cumulative potential-derived atomic multipole method

Abstract

In this paper, we propose a systematic method to include cumulatively atomic dipole moments and quadrupole moments in the fitting procedures of the potential-derived method to derive a set of atomic parameters to calculate the intermolecular electrostatic energy. This method is examined both qualitatively and quantitatively. The description of the charge distributions in polar molecules HF, H2O, and NH3 is agreeable to intuitions and the inverted lone-pair sites in H2O are explained naturally. It is also shown that atomic dipole moments and quadrupole moments should be included if one wants to calculate the electrostatic energy between molecules precisely. We also use Buckingham's model to calculate the orientations of some H-bonded complexes and explain the sources of nonlinear forces in terms of atomic dipole moments and quadrupole moments.