Unpolarizable molecular model describing electron distribution for treating halogen bonds

Abstract

This paper proposes an unpolarizable molecular model for treating halogen bonds that explicitly describes electron distributions. The orbital-like functions are defined as a linear combination of the primitive Gaussian functions for each atom that constitutes the molecule. The electron density of the entire molecule is described as a sum of the squares of these functions. The model evaluates the electrostatic and exchange repulsion terms based on the electron distribution, and thus, both these terms depend on the distribution. This model accurately describes the σ-hole of halogens and the total interaction energy of the halogen bonds in halogen/H2O systems.