Time-resolved low energy electron diffraction from large excited molecules on surfaces

• Antragsteller: Professor Dr. Herbert Over
• Fachliche Zuordnung: Physikalische Chemie von Festkörpern und Oberflächen, Materialcharakterisierung
• Förderung: Förderung von 2000 bis 2007
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 5261016

In order to watch processes on the molecular level, it is necessary to develop a technique that combines the time and space domain on a microscopic scale. For the case of surface chemistry the standard tool for structure determination is low energy electron diffraction (LEED). For time-resolved LEED experiments we shall develop an electron gun that produces ultra short and coherent electron pulses with an expected time resolution of less than 5 picoseconds. With this time-resolution we are able to study low-frequency modes of large adsorbed molecules such as the frustrated translation of C60 on Ag(100) by a pump & probe experiment. This experiment will serve as proof of principle for time-resolved LEED. The interpretation of the time dependent experimental LEED data requires an improved approach for the LEED calculations. From these experiments in combination with the elevated LEED data evaluation we want to determine how the once excited low-frequency mode of C60 damps (and dephases) with time (on the picosecond scale). These data may provide useful information about the coupling of the C60 molecule with the underlying substrate and neighbouring C60 molecules.

• DFG-Verfahren: Sachbeihilfen
• Internationaler Bezug: Schweiz
• Beteiligte Person: Privatdozent Dr. Thomas Greber