Research Subjects:



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 [3] 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.



Publications:

[1] A. Hauschild, K. Karki, B.C.C. Cowie, M. Rohlfing, F.S. Tautz, M. Sokolowski, Molecular distortions and chemical bonding of a large π-conjugated molecule on a metal surface. Phys. Rev. Lett. 94, 036106 (2005).
[2] A. Kraft, R. Temirov, S.K.M. Henze, S. Soubatch, M. Rohlfing, and F.S. Tautz, Lateral adsorption geometry and site-specific electronic structure of a large organic chemisorbate on a metal surface. Phys. Rev. B 74, 041402(R) (2006).
[3] S.K.M. Henze, O. Bauer, T.-L. Lee, M. Sokolowski, F.S. Tautz, Vertical bonding distances of PTCDA on Au(1 1 1) and Ag(1 1 1): Relation to the bonding type. Surf. Sci. 611, 1566 (2007).
[4] R. Temirov, S. Soubatch, A. Luican, F.S. Tautz, Free-electron-like dispersion in an organic monolayer film on a metal substrate. Nature 444, 350 (2006).
[5] L. Kilian, A. Hauschild, R. Temirov, S. Soubatch, A. Schöll, A. Bendounan, F. Reinert, T.-L. Lee, F. S. Tautz, M. Sokolowski, and E. Umbach, Role of intermolecular interactions on the electronic and geometric structure of a large π-conjugated molecule adsorbed on a metal surface. Phys. Rev. Lett. 100, 136103 (2008).

Collaborations:

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.


Address Director
Institute of Bio- and Nanosystems (IBN)
Institute 3: Institute of Thin Films and Interfaces 3 (IBN3)
Forschungszentrum Jülich GmbH
D-52425 Jülich 		Prof. Dr. Stefan Tautz
Tel.: ( 49) 24 61/61-4561
Fax: ( 49) 24 61/61-3907
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