Exploring the properties of valence electron based potential functions for the nonbonded interactions in atomistic force fields

TL;DR

This paper investigates valence electron-based potential functions for nonbonded interactions in atomistic force fields, demonstrating their advantages over traditional point charge models through accuracy assessments on small molecules.

Contribution

Introduces and compares three valence electron-based charge distribution models requiring only one adjustable parameter, improving electrostatic potential and interaction energy calculations.

Findings

Valence electron models outperform point charge models in accuracy.

Only one parameter needed for electrostatic potential in each model.

Systematic improvements in intermolecular energy predictions.

Abstract

The possibility to construct and parametrize the nonbonded interactions in atomistic force fields based on the valence electron structure of molecules is explored in this paper. Three different charge distribution models using simple valence electron based potential functions are introduced and compared. It is shown that the three models can be constructed such that they only require one adjustable parameter for the electrostatic potential of a molecule. The accuracy of the electrostatic potential is evaluated for the three models and compared to population-derived charges and higher order multipole moments for a set of 12 small molecules. Furthermore the accuracy and parametrization of the interaction energies of the three models is evaluated based on ab initio intermolecular interaction energies. It is shown that the valence electron potential models provide systematic advantages over conventional point charge models for the calculation of intermolecular interaction energies even with the very simple potential functions used here.