Parametrization of the Tkatchenko-Scheffler dispersion correction scheme for popular exchange-correlation density functionals: effect on the description of liquid water

TL;DR

This study optimizes dispersion correction parameters for popular density functionals and evaluates their impact on accurately modeling the structure and thermodynamics of liquid water.

Contribution

It provides optimized damping range parameters for seven density functionals to improve van der Waals correction accuracy in liquid water simulations.

Findings

Optimized parameters reduce errors in interaction energies.

Improved van der Waals corrections enhance water property predictions.

Certain functionals show significant improvements with the new parameters.

Abstract

We present a list of optimized damping range parameters $s_R$ to be used with the Tkatchenko-Scheffler van der Waals dispersion-correction scheme [Phys. Rev. Lett. 102, 073005 (2009)]. The optimal $s_R$ are obtained for seven popular generalized-gradient approximation exchange-correlation density functionals: PBE, RPBE, revPBE, PBEsol, BLYP, AM05 and PW91. The optimization is carried out in the standard way by minimizing the mean absolute error of the S22 test set, where the reference interaction energies are taken from coupled-cluster calculations. With the optimized range parameters, we assess the impact of van der Waals corrections on the ability of these functionals to accurately describe structural and thermodynamic properties of liquid water: radial distribution functions, self-diffusion coefficients and standard molar entropies.