Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 23: Methods in Computational Materials Modelling (methodological aspects, numerics)

MM 23.8: Vortrag

Mittwoch, 3. April 2019, 12:15–12:30, H44

Performance of van der Waals Methods at Non-Equilibrium Molecular Geometries — •Dennis Barton, Yasmine Al-Hamdani, and Alexandre Tkatchenko — Université de Luxembourg, Luxembourg, Luxembourg

An accurate description of van der Waals (vdW) dispersion interactions is a fundamental problem in electronic-structure calculations. These interactions are subtle, but of highest importance for the description of the structure, stability, and dynamics of biomolecules, chemical compounds, and materials.

Usually, approximate models for vdW interactions are used in combination with semi-local density functionals [1,2]. Common vdW methods are parametrized by one or more parameters, optimized for systems at equilibrium distances. Hence, their accuracy can only be granted at the energetic minimum.

We investigate vdW methods in terms of interatomic distances in small and weakly bound bimolecular complexes. We find a systematic increase of accuracy for the Many-Body Dispersion (MBD) method with respect to the intramolecular distance. In contrast, pairwise approaches (e.g. TS, D3) and non-local functionals show a non-systematic behavior.

Our analysis of the performance of vdW methods away from equilibrium geometries will greatly help to develop new methods with high accuracy everywhere on the potential-energy surface.

[1] Grimme et al., Chem. Rev. 116, 5105 (2016)

[2] Hermann et al., Chem. Rev. 117, 4714 (2017)