MOLECULAR ELECTROSTATIC CHARGE MODELS - A TOPOGRAPHICAL APPROACH

Electrostatic charge models for molecules have been developed by emplo ying the critical topographical features of the molecular electrostati c potential (MESP) as the ''fitting'' criterion. These models include one or more spherical Gaussians for incorporating the continuous elect ron-charge distribution in addition to the positive valued point charg es representing the nuclei. The model parameters (point charges, the o rbital exponents, and Gaussian centers) are optimized so as to mimic t he extremal characteristics of the corresponding quantum chemical MESP . The test cases reported here include methane, ethylene, and methanol molecules. The charge models developed using the present method are s een to satisfactorily reproduce the ab initio MESP and its extremal fe atures. (C) 1994 John Wiley & Sons, Inc.