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Multicenter point charge model for high‐quality molecular electrostatic potentials from AM1 calculations
Author(s) -
Rauhut Guntram,
Clark Timothy
Publication year - 1993
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540140502
Subject(s) - atomic orbital , chemistry , wave function , linear combination of atomic orbitals , centroid , atomic physics , charge (physics) , point particle , atom (system on chip) , computational chemistry , molecular physics , electron , physics , quantum mechanics , geometry , mathematics , computer science , embedded system
The natural atomic orbital/point charge (NAO‐PC) model based upon the AM1 wave function has been developed to calculate molecular electrostatic potentials (MEPs). Up to nine point charges (including the core charge) are used to represent heavy atoms. The positions and magnitudes of the eight charges that represent the atomic electron cloud are calculated from the natural atomic orbitals (NAOs) and their occupations. Each hybrid NAO is represented by two point charges situated at the centroid of each lobe. The positions of the centroids and the magnitudes of the charges were obtained by numerical integration of the Slater‐type hybrids and the results used to set up polynomials and look‐up tables that replace the integration step in the actual MEP calculation. The MEPs calculated using this method are found to be in better agreement with those obtained using RHF/6‐31G* than those obtained from the AM1 wave function using Coulson charges or with MOPAC‐ESP. The MEP calculations are extremely fast and have, for instance, been incorporated into an interactive graphics package. © 1993 John Wiley & Sons, Inc.