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O: Fachverband Oberflächenphysik
O 32: Poster Session - Organic Molecules on Inorganic Substrates: Adsorption and Growth
O 32.12: Poster
Montag, 16. März 2020, 18:15–20:00, P1C
Explaining surface polymorphism of acenequinones on Ag(111) with SAMPLE — •Andreas Jeindl1, Lukas Hörmann1, Jari Domke2, Alexander T. Egger1, Falko Sojka2, and Oliver T. Hofmann1 — 1Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Austria — 2Institute of Solid State Physics, Friedrich Schiller University Jena, Germany
Understanding (and modifying) the formation of surface polymorphs is still not straightforward as it is hardly known why specific structures form. Normally, the exponential growth of possible polymorphs with system size prohibits rigorous computational studies, that could explore the full configurational and thermodynamic search space. The peculiar physics that govern the interface formation, however, allow to reduce the search space and make the problem tractable.
In this contribution we use SAMPLE, a program package developed to efficiently predict energies for commensurate surface layers. It employs machine learning to suitably fit a physical energy model which consists only of molecule-substrate and molecule-molecule interactions. We perform a comprehensive structure search for a homologous series of acenequinones on Ag(111) to explain the mechanisms driving the formation of surface polymorphs and compare some of our results to experimental observations. Our research shows that the structures differ fundamentally. Insights from our model suggest that this originates mostly from the van-der-Waals interaction of the substrate with the backbone as well as the fact that upon increasing the backbone length, vdW interactions between the molecules become more important.