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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 82: Computational Materials Modelling - Solids and Molecules (joint session MM/CPP)

CPP 82.1: Vortrag

Mittwoch, 18. März 2020, 15:45–16:00, IFW B

Molecular Adsorption Potential Energy Surfaces and their Reproducibility — •Lukas Hörmann, Andreas Jeindl, and Oliver T. Hofmann — Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Molecular adsorption on surfaces depends on a range of mechanisms: covalent bonds, charge transfer and van-der-Waals (vdW) interactions shape the potential energy surface (PES), making the PES key to understanding molecule-substrate interfaces. Describing these interfaces with density functional theory requires a wise selection of the exchange correlation functional and vdW correction scheme. To explore the robustness of the PES with respect to the choice of method, we present a benchmark of common local, semi-local and non-local functionals in combination with various vdW corrections. We investigate these methods using perylenetetracarboxylic dianhydride (PTCDA) on Ag(111), one of the most frequently studied systems.

We use an in-house developed Gaussian process regression algorithm, which requires only about 50 DFT calculations as input to generate a PES with DFT accuracy. This allows a detailed analysis of the PES's features, such as positions and energies of minima and saddle points. Comparing the results from different exchange correlation functionals enables us to identify trends and differences between the approaches. Finally, we compare key features, such as local minima, with experimental data to determine a "quality seal" for the different functionals and vdW corrections.