Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)
O 36.34: Poster
Dienstag, 15. März 2011, 18:30–22:00, P4
Bisterpyridine adlayers on metal surfaces as 2D model systems - A STM study — •Thomas Waldmann1, Harry E. Hoster1,2, and R. Jürgen Behm1 — 1Ulm University, Institute of Surface Chemistry and Catalysis, 89069 Ulm, Germany — 2Current address: Technische Universität München, Centre for Electromobility, 50 Nanyang Drive, Singapore 637553
Adlayers of the bisterpyridine derivative 2,4’-BTP on Au(111), Ag(111) and Ag(100) are used as two-dimensional (2D) model systems for studying self-assembly and for direct observation of (reaction)dynamics by scanning tunneling microscopy (STM).
(i) At low coverages, we find a preference for a step-crossing behavior of 2,4’-BTP that can be explained by the intramolecular building blocks of the adsorbate. The self-organization on terraces is influenced by (N...metal)-type molecule-substrate interactions, producing 12 preferred azimuthal orientations of the adsorbates with respect to the close packed surface directions in both, ordered and disordered areas [1]. (ii) Domains of freely rotating molecules, which are stabilized significantly by rotational entropy resulting from the large moment of inertia of 2,4’-BTP [2] exist in a dynamic equilibrium with non-rotating molecules at 300 K. We compare the stabilization by rotational entropy with that for other typical small and large adsorbates. (iii) Ordered monolayers of 2,4’-BTP on Ag(111) are used as a model system for direct STM observation of the reaction between the adlayer and oxygen to a N-oxide network.
T.Waldmann et al., ChemPhysChem 11, 1513 (2010).
M.Roos et al., PCCP 12, 812 (2010).