Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Inorganic/Organic Interfaces
O 41.1: Poster
Dienstag, 17. März 2015, 18:15–21:00, Poster B
LEED-IV-Analysis of large planar molecules on Ag surfaces — •Ina Krieger1,3, Johannes Ingenmey1, Georg Held2, Christian Kumpf3, and Moritz Sokolowski1 — 1Institut für Physikalische und Theoretische Chemie der Universität Bonn, Wegelerstr. 12, 53115 Bonn, Germany — 2Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, and Diamond Light Source, Didcot, OC11 0DE, UK — 3Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
The atomic coordinates of large aromatic molecules adsorbed on surfaces are of great interest in the context of understanding the details of interaction and chemical bonding between the molecules and the substrate. Normal incidence X-ray standing waves (NIXSW) is considered to be the only technique which can provide this information with sufficient precision. Here we report on an alternative, namely the I(V)-analysis of low energy electron diffraction (LEED-IV) on two model molecules, which have been investigated by NIXSW before. The intention was to gain additional structural information by LEED-IV and to test the potential of LEED-IV for larger molecules.
We present results on PTCDA/Ag(100) showing an encouraging agreement with those from DFT and NIXSW studies. We obtained a good Pendry R-factor of 0.19 and derive additional structure information on the internal geometry of the molecules, in particular regarding vertical distortions of the perylene core, as well as the buckling of the substrate surface. In addition, we will present first results of a LEED-IV study on the adsorption of NTCDA on Ag(111). Supported by the DFG.