Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 10: Adsorption an Oberfl
ächen I
O 10.1: Vortrag
Freitag, 4. März 2005, 15:45–16:00, TU EB301
The Adsorption of Triptycene on Au(111): a bilayer growth stabilised by intermolecular π-π interactions — •I.F. Torrente1,2, N. Henningsen1, and J. I. Pascual1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany — 2Institut Català de Nanotecnologia, Campus UAB, Bellaterra, Barcelona, Spain
The adsorption of triptycene molecules (C20H14) on Au(111) is studied by means of Low-Temperature Scanning Tunnelling Microscopy and Spectroscopy. Triptycene is a model system to investigate the balance between the tendency of the aromatic units to bond flat, parallel to a metal surface, and the intermolecular π-π interactions. In planar aromatic molecules, the interaction of π states with the metal electronic states usually dominates. The structure of triptycene frustrates partially such planar configuration. As a result, triptycene interaction with the Au(111) metal surface is described by a weak physisorption. As soon as the substrate temperature is above a few tenths of K, Triptycene ensemble in self-assembled molecular islands with a characteristic bilayer structure. The interpretation of such growth mechanism is done on the basis of the dominant role of stronger intermolecular interactions respect to physisorption energies.