Nonlocal van der Waals functionals: The case of rare-gas dimers and solids

TL;DR

This paper evaluates various nonlocal van der Waals density functionals for rare-gas dimers and solids, demonstrating their improved accuracy over traditional methods in capturing weak dispersion interactions.

Contribution

The study systematically tests different vdW functionals on rare-gas systems, providing insights into their accuracy and energy decomposition analysis compared to standard approaches.

Findings

vdW functionals outperform semilocal methods in weak interactions

energy decomposition reveals the physical basis of functional performance

nonlocal functionals provide consistent results across systems

Abstract

Recently, the nonlocal van der Waals (vdW) density functionals [M. Dion, H. Rydberg, E. Schroeder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)] have attracted considerable attention due to their good performance for systems where weak interactions are important. Since the physics of dispersion is included in these functionals, they are usually more accurate and show less erratic behavior than the semilocal and hybrid methods. In this work, several variants of the vdW functionals have been tested on rare-gas dimers (from He2 to Kr2) and solids (Ne, Ar, and Kr) and their accuracy compared to standard semilocal approximations supplemented or not by an atom-pairwise dispersion correction [S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, J. Chem. Phys. 132, 154104 (2010)]. An analysis of the results in terms of energy decomposition is also provided.