Frankfurt 2006 – scientific programme

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MO: Molekülphysik

MO 71: Dynamics and Spectroscopy at Interfaces

MO 71.1: Talk

Friday, March 17, 2006, 10:40–10:55, H12

Ultrafast heterogeneous electron transfer: escape dynamics of injected electrons — •Lars Gundlach, Ralph Ernstorfer, Jodi Szarko, Antje Neubauer, Liana Socaciu-Siebert, and Frank Willig — Hahn-Meitner-Institute, Department: Dynamics of Interfacial Reactions SE4, Glienickerstrasse 100, 14109 Berlin, Germany

So far, most investigations of heterogeneous electron transfer focused on the time scale the electrons take to leave the molecules. Here, we report on the dynamics taking place after the electron has left the molecule.
Ultrafast electron escape dynamics following excitation of the interfacial charge transfer complex of catechol prepared on the rutile TiO₂(110) surface was investigated with femtosecond two-photon photoemission.
Photo-induced interfacial charge transfer was instantaneous. Thus, the rise of the signal was controlled by the crosscorrelation function. The energy distribution of the hot electrons generated at the surface was measured as 2PPE spectra. The decay of the 2PPE signal was non-exponential with time constants ranging from 10 fs to picoseconds. It was attributed to the release of the electrons from the surface and escape into the bulk of the semiconductor.