Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 17: Zeitaufgelöste Spektroskopie I

O 17.4: Vortrag

Dienstag, 25. März 2003, 12:00–12:15, FOE/ORG

Femtosecond Electron Dynamics in Ru(0001): Electron Temperature and Quasiparticle Lifetimes in Bulk and Image Potential States — •Martin Lisowski, Uwe Bovensiepen, Cornelius Gahl, Panagiotis Loukakos, Julia Stähler, and Martin Wolf — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin

Femtosecond photoinduced chemical reactions on metal surfaces are driven by hot electrons [1]. For a detailed understanding, quantitative information on the hot electron dynamics in the metal is important. Therefore, we have measured the temporal evolution of the electron distribution in Ru(0001) after excitation by ultrashort laser pulses with variable fluence up to 1 mJ/cm² using time-resolved 2-photon-photoelectron spectroscopy. The electron distribution shows a not fully thermalized hot tail and features of the unoccupied d-band of Ru. In the low fluence limit we have determined the relaxation times which will be discussed in view of quasiparticle lifetimes. In addition, we report binding energies and relaxation times for the n=2 and n=3 image potential states.

[1] M. Bonn, S. Funk, Ch. Hess, D.N. Denzler, C. Stampfl, M. Scheffler, M. Wolf, G. Ertl, Science 285, 1042 (1999)