Precision measurements of adsorption height and molecular conformation of complex organic adsorbates
Giuseppe Mercurio, Sergey Subach, Christian Kumpf, Stefan Tautz
For prototypical π-conjugated PTCDA molecule adsorbed on different metallic surfaces, we study the interaction at interface and its impact on structural - adsorption height and molecular conformation - and electronic properties of the adsorbate [1,2]. Varying the substrate - Ag(111), Ag(100), Ag(110), Au(111), Ni(111) - we control the interaction potential  at the interface. Correspondingly the bonding mechanism [4,5] can be descriebed. Probing of local electronic properties for individual PTCDA molecules is achieved with low temperature STM by means of tunneling spectroscopy. For general characterization of electronic state of molecular layers, photoelectron spectroscopy is used. Vertical adsorption geometry including possible bending of a molecule is studied with Normal Incidence X-ray Standing Wave method at the European Synchrotron Radiation Facility (Grenoble), beam line ID32.
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M. Sokolowski, Univ. Bonn,
M. Rohlfing, Univ. Osnabrück,
A. Schöll, F. Reinert, Univ. Würzburg,
T.-L. Lee, Diamond Light Source, UK,
J. Zegenhagen, ESRF, France.