Density Functional Theory Approach to Noncovalent Interactions via Interacting Monomer Densities

TL;DR

This paper details a DFT+dispersion method that combines dispersion-free DFT interaction energies with separate dispersion calculations, using a self-consistent polarization approach to accurately model noncovalent interactions.

Contribution

It introduces a novel formalism for noncovalent interactions that integrates dispersion effects into DFT via interacting monomer densities and the Pauli blockade technique.

Findings

Good agreement with benchmark interaction energies

Effective modeling of diverse molecular complexes

Applicable to rare-gas, hydrogen-bonded, and pi-electron systems

Abstract

A recently proposed "DFT+dispersion" treatment (Rajchel et al., Phys. Rev. Lett., 2010, 104, 163001) is described in detail and illustrated by more examples. The formalism derives the dispersion-free density functional theory (DFT) interaction energy and combines it with the dispersion energy from separate DFT calculations. It consists in the self-consistent polarization of DFT monomers restrained by the exclusion principle via the Pauli blockade technique. Within the monomers a complete exchange-correlation potential should be used, but between them only the exact exchange operates. The applications to wide range of molecular complexes from rare-gas dimers to H-bonds to pi-electron interactions show good agreement with benchmark values.