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O: Fachverband Oberflächenphysik
O 78: Surface Dynamics I
O 78.7: Talk
Thursday, March 14, 2013, 17:30–17:45, H42
Helium-3 spin echo measurements and simulation of pentacene on pentacene surface diffusion — •Paul Rotter1, Antonia Morherr2, Barbara Lechner3, David Chisnall3, Andrew Jardine3, John Ellis3, William Allison3, Bruno Eckhardt1, and Gregor Witte2 — 1Komplexe Systeme, Philipps-Universität Marburg, 35032 Marburg, Germany — 2Molekulare Festkörperphysik, Philipps-Universität Marburg, 35032 Marburg, Germany — 3Cavendish Laboratory, Cambridge, CB3 0HE, UK
With the Helium-3 spin echo technique (3HeSE) surface diffusion processes can be directly observed at their characteristic length scales (nm) and time scales (ps). While previous experiments focused on small adsorbates and metal surfaces, we advance to comparatively large organic diffusing adsorbates and organic surfaces. In this study a coplanar monolayer of pentacene chemisorped on Cu(110) was used as a well characterized organic surface on which isolated pentacene molecules diffuse. 3HeSE measurements which contain a complete statistical description of the adsorbate motion were carried out for different azimuthal directions of the surface. To extract the different processes that contribute to the diffusion, we use molecular dynamics simulations to compare to and reproduce key features of the experimental results. The potential energy surfaces needed for those simulations are constructed via molecular mechanics.