Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 42: Symposium Electron transfer processes II

O 42.4: Fachvortrag

Thursday, March 30, 2006, 16:30–17:00, WIL C207

Electron induced isomerization — •Karina Morgenstern — Universität Hannover, Institut für Festkörperphysik, Appelstr. 2, 30167 Hannover

With the scanning tunneling microscope (STM) it is possible to induced chemical reactions on a single molecule basis by electrons tunneling inelastically from the STM tip into a molecule. The method is based on high-resolution imaging at low-temperature (5K) that allows us to identify different groups within the molecule. Chemical reactions are induced by injecting selectively electrons into specific parts of the molecule. The success of the manipulation is visualized in the recorded tunneling current during the manipulation and in STM images taken afterwards. We will present isomerization for two molecules of different complexity, specifically substituted benzene molecules (chloronitrobenzene), and photochrome molecules (azobenzene derivate). The energies needed for the reactions are remarkably low and can be best understood in terms of weakened bonds on the surface in connection with direct reformation of a new bond.