Van der Waals Energies in Density Functional Theory

TL;DR

This paper introduces a practical method to accurately include Van der Waals energies in density functional theory calculations, improving results for interactions between separated systems.

Contribution

A new procedure is proposed to incorporate Van der Waals energies into density functional theory, enabling accurate calculations across various inter-system distances.

Findings

Accurate asymptotic H-He and He--He interaction energies obtained.

Method works seamlessly for small and large inter-system distances.

Improves the accuracy of DFT for Van der Waals interactions.

Abstract

In principle, density functional theory yields the correct ground-state densities and energies of electronic systems under the action of a static external potential. However, traditional approximations fail to include Van der Waals energies between separated systems. This paper proposes a practical procedure for remedying this difficulty. Our method allows seamless calculations between small and large inter-system distances. The asymptotic H-He and He--He interactions are calculated as a first illustration, with very accurate results.