# Van der Waals Interactions in DFT using Wannier Functions without empirical parameters

## TL;DR

This paper introduces a parameter-free method for incorporating van der Waals interactions into Density Functional Theory using Maximally-Localized Wannier functions, improving accuracy over previous approaches.

## Contribution

The paper presents a novel DFT/vdW-WF2-x method that replaces empirical damping with a physically-based estimate of Pauli exchange repulsion, enhancing the description of vdW systems.

## Key findings

- Systematic improvement in vdW-bonded system descriptions
- Accurate results for S22 molecular database
- Effective modeling of Ar-graphite interactions

## Abstract

A new implementation is proposed for including van der Waals (vdW) interactions in Density Functional Theory (DFT) using the Maximally-Localized Wannier functions (MLWFs), which is free from empirical parameters. With respect to the previous DFT/vdW-WF2 method, in the present DFT/vdW-WF2-x approach, the empirical, short-range, damping function is replaced by an estimate of the Pauli exchange repulsion, also obtained by the MLWFs properties. Applications to systems contained in the popular S22 molecular database and to the case of an Ar atom interacting with graphite, and comparison with reference data, indicate that the new method, besides being more physically founded, also leads to a systematic improvement in the description of vdW-bonded systems.