Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Poster Monday: Organic Molecules at Surfaces 1

O 17.2: Poster

Montag, 5. September 2022, 18:00–20:00, P4

Navigating the Polymorph-Jungle with Optimal Control techniques — •Simon Hollweger, Anna Werkovits, Richard K. Berger, and Oliver T. Hofmann — Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Properties of organic-inorganic interfaces are strongly dependent on the arrangement of the molecules on the surface. However, achieving a controlled growth of a polymorph with preferable physical properties is not straightforward at all - especially for metastable polymorphs.

In principle, starting from a thermodynamically easily accessible polymorph, kinetics can be utilized to stabilize a metastable polymorph. This can be done by promoting certain structural transitions by a-priori unknown sequentially changing growth conditions. Depending on the complexity of the transition network, often only a limited yield of the target polymorph can be reached during growth.

To computationally maximize the yield of the desired structure we use Optimal Control techniques. Therein, process parameters like temperature and pressure are varied to optimize parameter protocols. The transition network of our model system TCNE/Cu(111) is obtained via a combination of Transition State Theory and Density Functional Theory.