Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 28: Surface reactions II
O 28.4: Vortrag
Dienstag, 28. März 2006, 16:30–16:45, WIL C207
Hot electron mediated associative desorption of hydrogen from Ru(001): insights from theory and experiment — •Steffen Wagner1, Christian Frischkorn1, Martin Wolf1, Mats Persson2, and Alan C. Luntz3 — 1Freie Universität Berlin — 2Chalmers University of Technology, Göteborg — 3Dansk Fysik Institut Odense
Hot electron mediated associative desorption of hydrogen from a hydrogen covered Ru(001) surface was investigated both experimentally and theoretically. The hot electron distribution created by femtosecond-laser irradiation was proven to mediate H2 desorption [1]. The desorbing hydrogen molecules were investigated regarding isotope effects, fluence dependence and energy transfer to the different molecular degrees of freedom [1, 2]. For the latter, different energy content in the different degrees of freedom was found. Those experimental findings are compared with the outcome of two-dimensional trajectory calculation, which take into account the electron mediated activation of the adsorbate via electronic friction. The friction coefficients are obtained from DFT calculations. This concept has been proven to be successful for the consideration of non-adiabatic effects in activated associative desorption and vibrational damping of adsorbed molecules [3,4]. Thus, we are able to give a microscopic description of the experimental observations.
[1] Denzler et al, Phys. Rev. Lett. 91, 226102 (2003) [2] Wagner et al, Phys. Rev. B 72, 205404 (2005); [3] Luntz, Persson, J.Chem. Phys. 123, 074704 (2005) [4] Persson, Hellsing, Phys. Rev. Lett. 49, 662 (1982)