Van der Waals Interactions in Density Functional Theory by combining the Quantum Harmonic Oscillator-model with Localized Wannier Functions

TL;DR

This paper introduces a generalized van der Waals correction method for Density Functional Theory by integrating the Quantum Harmonic Oscillator model with Wannier Functions, capturing many-body effects and applicable to molecules and extended systems.

Contribution

It extends previous Wannier-based vdW methods to include non-separable fragments and higher-order interactions, enhancing accuracy and applicability.

Findings

Accurately predicts binding energies in the S22 database.

Successfully applied to graphite and H2 on Cu(111) surfaces.

Shows improved results over existing vdW-corrected DFT schemes.

Abstract

We present a new scheme to include the van der Waals (vdW) interactions in approximated Density Functional Theory (DFT) by combining the Quantum Harmonic Oscillator model with the Maximally Localized Wannier Function technique. With respect to the recently developed DFT/vdW-WF2 method, also based on Wannier Functions, the new approach is more general, being no longer restricted to the case of well separated interacting fragments. Moreover, it includes higher than pairwise energy contributions, coming from the dipole--dipole coupling among quantum oscillators. The method is successfully applied to the popular S22 molecular database, and also to extended systems, namely graphite and H$_2$ adsorbed on the Cu(111) metal surface (in this case metal screening effects are taken into account). The results are also compared with those obtained by other vdW-corrected DFT schemes.