Hannover 2003 – wissenschaftliches Programm

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A: Atomphysik

A XIV: HV XIV

A XIV.1: Hauptvortrag

Donnerstag, 27. März 2003, 11:30–12:00, B305

Chemistry with Electrons: Modification of Surfaces and Thin Films — •Petra Swiderek — Institut für Physikalische Chemie, Universität zu Köln, Luxemburger Str. 116, 50939 Köln

Chemical reactions induced by low-energy electrons are not only important as fundamental steps of processes following the production of secondary electrons under the effect of high-energy radiation. They are also interesting as a tool for modifying or patterning surfaces of molecular materials such as ultrathin organic coatings. This can be done on a macroscopic scale by rastering the material with a focussed beam of electrons, exposing it to electrons through a mask, or on a nanometer scale by using the tip of a scanning tunneling microscope as a local electron source. Although examples of such modifications are known, the reaction mechanisms are far from being understood. Therefore fundamental spectroscopic studies of the reactions taking place at or near the surface of ultrathin molecular films are performed in my group. The use of high-resolution electron energy loss spectroscopy allows us to irradiate the samples and analyse the modifications at the same time. This contribution will present examples of such modifications and discuss the experimental approach that allows us to obtain absolute cross sections for specific electron-induced reactions.