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O: Fachverband Oberflächenphysik

O 18: Organic/bio Molecules on Metal Surfaces II

O 18.10: Vortrag

Montag, 11. März 2013, 18:15–18:30, H38

Nanoscale Control of Molecular Conformation via Tuned Coupling to a Substrate — •Hasmik Harutyunyan¹, Martin Callsen², Tobias Allmers¹, Vasile Caciuc², Stefan Blügel², Nicolae Atodiresei², and Daniel Wegner¹ — ¹Westfälische Wilhelms-Universität Münster Wilhelm-Klemm-Str. 10, 48149 Münster, Deutschland — ²Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) Forschungszentrum Jülich and JARA 52425 Jülich, Deutschland

In recent years the adsorption of organic molecules on noble-metal has shown large interest. Here, it is important to understand the electronic interaction between a gas-phase molecules and the surface, which leads to hybridization and can induce charge transfer. We have investigated the conformation of cyclooctatetraene (COT) on different noble metals by means of low-temperature scanning tunneling microscopy combined with density functional theory. Highly resolved STM images in conjunction with STM simulations enable the unambiguous identification of molecular conformations. The results show, that COT can by stabilized in different conformations by varying its coupling to the noble-metal surface. We find weak physisorption and the tube conformation on Au(111), as know for the gas-phase molecule. On Ag(100) and Cu(100) COT is chemisorbed and planar, as known for charged gas-phase molecules. The conformation of COT can even be manipulated on Au(111) by utilizing nanoscale variations of the molecule-surface interaction. This mechanical and electronic control makes COT an interesting candidate for versatile molecular switches.