An <i>ab initio</i> study of molecular charge distribution and electrostatic potentials: Role of hybridization displacement charge

Abstract

Hybridization displacement charges (HDC), when combined with Löwdin charges, preserve SCF molecular dipole moments. One can generate near <i>ab initio</i> quality MEP maps using HDC combined with Löwdin charges obtained employing semiempirical methods. HDC are obtained using off-diagonal elements of the Löwdin population matrix, and correspond to charges located at different points near atoms in molecules, including lone pairs. In view of a great usefulness of HDC as evidenced by semiempirical calculations, a method of computing HDC using <i>ab initio</i> wave functions has been developed. It has been applied to compute charge distributions, dipole moments and molecular electrostatic potential maps of certain molecules at the SCF level using the 6-31 G** basis set. The molecular properties obtained using HDC and CHelpG charges are compared.