Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 65: Metal substrates: Adsorption of organic / bio molecules VII
O 65.4: Vortrag
Donnerstag, 17. März 2011, 12:00–12:15, PHY C213
The effect of molecular vibration on the Resonant Auger Raman spectra of Sn-phthalocyanine thin films — Marc Haeming1, Johannes Ziroff1, Lothar Weinhardt1, •Achim Schöll1, and Friedrich Reinert1,2 — 1Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg — 2KIT, Gemeinschaftslabor für Nanoanalytik, D-76021 Karlsruhe
On the example of epitaxially grown layers of Tin-phthalocyanine (SnPc) as well as ultrathin SnPc layers adsorbed on a monolayer of PTCDA/Ag(111) we demonstrate the capabilities of Resonant Auger Raman Spectroscopy in analyzing the electron-vibration coupling in thin films of large organic molecules and at their interfaces. The constant initial state signal of particular SnPc levels is substantially enhanced by autoionization and participant decay of the core excited state. We show that the fine structure of the autoionization signal can differ significantly from that of the direct photoemission signal, which is related to electron-vibration coupling. Moreover, continuous modifications of the vibronic fine structure of the autoionization spectra are observed when tuning the excitation energy through an absorption resonance. By comparing SnPc in multilayer samples to SnPc on PTCDA we can demonstrate that these effects are obviously very sensitive to the molecular environment, even in case of weak, predominantly non-covalent interaction. Therefore Resonant Auger Raman Spectroscopy can provide new insight into electron-vibration coupling and into intermolecular interaction in films of organic molecules.