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Functional molecules on surfaces and their assembly into pre-defined architectures are key challenges in nanotechnology and of interest in various fields from molecular electronics over novel materials to molecular machines. Various examples of functional molecules, studied by scanning tunneling microscopy (STM) under ultrahigh vacuum conditions, will be discussed. Specifically designed molecular building blocks are connected to two-dimensional networks or one-dimensional chains, which can act as molecular wires. On the other hand, chemical processes within individual molecular can be controlled via their environment. This was observed for molecular switches, where the atomic-scale surroundings cause drastic changes in their switching probability. It could be shown that the rate of an intramolecular hydrogen transfer reaction can be tuned up and down by single atoms in the vicinity of the molecule. Single atoms were also found to modify the appearance of adsorbed molecules in STM images during their diffusion underneath the molecules. A combination of the two approaches will be discussed, potentially leading to heterogeneous molecular nanostructures that contain functional molecules.

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Leonhard Grill, University of Graz
Seminar room of the Institute of Physics II
Contact: Alexander Grueneis