Novel point charge models: reliable instruments for­molecular electrostatic

Abstract

AbstractA novel method to compute atomic charge distribution is proposed. The starting data for the computation are the topology of a molecule and electronegativities of either constituent atoms or atomic orbitals. The topology of a molecule is represented by a molecular graph or, in a more advanced model, by an orbital graph that reflects an orbital constitution of atoms. The distinctive feature of the method is that the starting atomic (orbital) electronegativities equilibrate in the same fashion that electrical potentials do in the nodes of a closed electrical network. Thus, the well‐developed formalism of the theory of electrical circuits was applied for computation of partial atomic charges. In addition, the problem of parametrization of halogens was solved using a specially developed procedures. Comparison of the obtained charges with those produced by means of various computational schemes [Partial Equalization of Orbital Electronegativities (PEOE), Mulliken population analysis, natural population analysis, Bader's AIM, method of generalized atomic polar tensors (GAPT) and an electrostatic potential‐based method, CHELPG] and with some molecular spectral characteristics proves that both models, but especially the orbital graph charge model, provide fast, convenient and reliable methods to calculate theoretically justifiable atomic charges for a variety of chemical species. The developed charge models are well suited for application in many areas of molecular modeling and QSAR/QSPR studies. Copyright © 2001 John Wiley & Sons, Ltd.