Van der Waals Interactions in DFT using Wannier Functions: improved $C_6$ and $C_3$ coefficients by a new approach

TL;DR

This paper introduces a new DFT method using Wannier functions that improves the calculation of van der Waals coefficients, specifically $C_6$ and $C_3$, for molecules and surfaces.

Contribution

The paper presents the DFT/vdW-WF2 approach, a simplified and more accurate method for evaluating van der Waals interactions in DFT using Wannier functions.

Findings

Improved $C_6$ coefficients for molecular dimers.

Better estimation of $C_3$ coefficients for molecule-surface interactions.

Preliminary results show enhanced accuracy over previous methods.

Abstract

A new implementation is proposed for including van der Waals interactions in Density Functional Theory using the Maximally-Localized Wannier functions. With respect to the previous DFT/vdW-WF method, the present DFT/vdW-WF2 approach, which is based on the simpler London expression and takes into account the intrafragment overlap of the localized Wannier functions, leads to a considerable improvement in the evaluation of the $C_6$ van der Waals coefficients, as shown by the application to a set of selected dimers. Preliminary results on Ar on graphite and Ne on the Cu(111) metal surface suggest that also the $C_3$ coefficients, characterizing molecule-surfaces van der Waals interactions are better estimated with the new scheme.