Representation of the molecular electrostatic potential by a net atomic charge model

Abstract Electrostatic potentials and Mulliken net atomic charges were calculated from STO ‐3G, 6‐31G, and 6‐31G** SCF ‐ MO wavefunctions for hydrogen fluoride, water, ammonia, methane, acetylene, ethylene, carbon dioxide, formaldehyde, methanol, formamide, formic acid, acetonitrile, diborane, and carbonate ion. In each case optimized net atomic charges (potential‐derived charges) were also obtained by fitting the electrostatic potentials calculated directly from the wavefunctions in a shell enveloping the molecules outside of their van der Waals surfaces. The electrostatic potentials calculated from the potential‐derived charge distributions were then compared with the defined quantum mechanical electrostatic potentials and with the electrostatic potentials of the Mulliken charge distributions.