Atomic charges derived from electrostatic potentials: A detailed study

TLDR

A new algorithm for fitting atomic charges to molecular electrostatic potentials is presented. The algorithm is non‑iterative, rapid, and examines the impact of using experimental versus optimized geometries. The algorithm yields accurate atomic charges that reproduce SCF dipole moments, with the 3‑21G basis set providing consistently good results in reasonable time across a range of molecules.

Abstract

Abstract A new algorithm for fitting atomic charges to molecular electrostatic potentials is presented. This method is non‐iterative and rapid compared to previous work. Results from a variety of gaussian basis sets, including STO‐3G, 3‐21G and 6‐31G*, are presented. Charges for a representative collection of molecules, comprising both first and second row atoms and anions are tabulated. The effects of using experimental and optimized geometries are explored. Charges derived from these fits are found to adequately reproduce SCF dipole moments. A small split valence representation, 3‐21G, appears to yield consistently good results in a reasonable amount of time.