Berlin 2008 – scientific programme
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O: Fachverband Oberflächenphysik
O 43: Poster Session II - MA 141/144 (Surface Spectroscopy on Kondo Systems; Frontiers of Surface Sensitive Electron Microscopy; Methods: Scanning Probe Techniques+Electronic Structure Theory+Other; Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation; joined by SYNF posters)
O 43.15: Poster
Tuesday, February 26, 2008, 18:30–19:30, Poster F
Dynamic Force Microscopy: Fundamental mechanism of energy dissipation for organic molecules — •Markus Fendrich1, Kai Ruschmeier2, Christian Weiss1, Manfred Lange1, Tobias Kunstmann1, André Schirmeisen2, and Rolf Möller1 — 1Fachbereich Physik, Universität Duisburg-Essen, D-47048 Duisburg — 2CeNTech Center for NanoTechnology, Heisenbergstr. 11, D-48149 Münster
In frequency modulation atomic force microscopy (FM-AFM), the damping signal reveals information about energy dissipation processes within the tip-sample system with high lateral resolution.[1] However, the mechanisms of energy dissipation are still not fully understood; especially for organic molecular systems, few results have been achieved so far. We present experimental data on the topography and dissipation of 3,4,9,10 perylene-tetracarboxylic dianhydride (PTCDA) on Ag(111). The molecules are known to form stable islands at sub-monolayer coverage.[2] We achieved molecular resolution in the topography and the damping signal alike. The damping signal of the PTCDA molecules shows a sub-molecular contrast, revealing two peaks at the ends of each molecule. The origin of this dissipation signal is still under debate; a tip-induced switching of the functional groups of each molecule might act as a channel for energy dissipation.
[1] S. Morita et al., Noncontact Atomic Force Microscopy, Springer (2002) [2] K. Glöckler et al., Surf. Sci. 405, 1 (1998)