Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)
O 35.33: Poster
Dienstag, 12. März 2013, 18:15–21:45, Poster B1
Simulating Photoelectron Diffraction Measurements of Fe-Porphyrins on Ag(111) — •Michael Greif1, Tibor Nagy2, Maksym Soloviov2, Luca Castiglioni1, Markus Meuwly2, Jürg Osterwalder1, and Matthias Hengsberger1 — 1Physik Institut, Universität Zürich, Winterthurerstrasse 190, 8052 Zürich, Schweiz — 2Department of Chemistry, University of Basel Klingelbergstrasse 80, 4056 Basel, Schweiz
Combing DFT- and force field calculation for iron-porphyrins on an Ag(111) surface not only yields parameters for the equilibrium structure of the molecules adsorbed on the surface, but also information about their dynamics. An experimental means enabling one to visualize structural dynamics are photoelectron diffraction measurements. In these experiments photoelectrons emitted from a molecular atom are coherently scattered by their neighboring atoms. Interference effects thus create a diffraction pattern in the photoelectron signal that is recorded by scanning the half sphere above the sample. From this pattern the structural parameters of the system can be found with a resolution on the sub Angstrom scale. An important analysis tool for those measurements are single scattering cluster (SSC) calculations, which can simulate the experimental outcome. Using Fe-porphyrin as an example we show how time resolved photoelectron diffraction may be used as tool to determine structural dynamics. By combining force-field computations and SSC calculations, it is possible to follow the molecular trajectories while the excited molecule crosses a conical intersection from the excited singlet state to the triplet ground state.