Communication: Charge-Population Based Dispersion Interactions for Molecules and Materials

TL;DR

This paper presents a charge-population based method to derive atomic dispersion coefficients and polarizabilities, enabling dispersion corrections in electronic structure calculations without electron-density partitioning.

Contribution

It introduces a system-independent approach to calculate dispersion parameters from charge analysis, compatible with semi-empirical methods and tight-binding Hamiltonians.

Findings

Method achieves accuracy comparable to density-based approaches.

Successfully integrated with the DFTB method for hybrid interfaces.

Demonstrated effectiveness on molecular dimers, crystals, and complexes.

Abstract

We introduce a system-independent method to derive effective atomic C$_6$ coefficients and polarizabilities in molecules and materials purely from charge population analysis. This enables the use of dispersion-correction schemes in electronic structure calculations without recourse to electron-density partitioning schemes and expands their applicability to semi-empirical methods and tight-binding Hamiltonians. We show that the accuracy of our method is en par with established electron-density partitioning based approaches in describing intermolecular C$_6$ coefficients as well as dispersion energies of weakly bound molecular dimers, organic crystals, and supramolecular complexes. We showcase the utility of our approach by incorporation of the recently developed many-body dispersion (MBD) method [Tkatchenko et al., Phys. Rev. Lett. 108, 236402 (2012)] into the semi-empirical Density Functional Tight-Binding (DFTB) method and propose the latter as a viable technique to study hybrid organic-inorganic interfaces.