Evaluating dispersion forces for optimization of van der Waals complexes using a non-empirical functional

Alya A. Arabi, Zayed University

ORCID Identifiers

0000-0003-3664-314X

Document Type

Conference Proceeding

Source of Publication

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences

Publication Date

11-13-2016

Abstract

© 2016 The Author(s) Published by the Royal Society. All rights reserved. Modelling dispersion interactions with traditional density functional theory (DFT) is a challenge that has been extensively addressed in the past decade. The exchange-dipole moment (XDM), among others, is a non-empirical add-on dispersion correction model in DFT. The functional PW86+PBE+XDM for exchange, correlation and dispersion, respectively, compromises an accurate functional for thermochemistry and for van der Waals (vdW) complexes at equilibrium and non-equilibrium geometries. To use this functional in optimizing vdW complexes, rather than computing single point energies, it is necessary to evaluate accurate forces. The purpose of this paper is to validate that, along the potential energy surface, the distance at which the energy is minimum is commensurate with the distance at which the forces vanish to zero. This test was validated for 10 rare gas diatomic molecules using various integration grids and different convergence criteria. It was found that the use of either convergence criterion, 10-6 or 10-8, in Gaussian09, does not affect the accuracy of computed optimal distances and binding energies. An ultrafine grid needs to be used when computing accurate energies using generalized gradient approximation functionals. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

ISSN

1364-503X

Publisher

Royal Society of London

Volume

374

Issue

2080

First Page

20160145

Disciplines

Computer Sciences

Keywords

Computing forces, Density functional theory, Dispersion interactions, Exchange-hole dipole moment model, Van der Waals complexes

Scopus ID

84992146103

Indexed in Scopus

yes

Open Access

yes

Open Access Type

Bronze: This publication is openly available on the publisher’s website but without an open license

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