Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)
O 24.46: Poster
Mittwoch, 26. März 2003, 14:30–17:30, P1
Six-dimensional quantum study of the dissociative adsorption of H2 on Pd(110) — •Arezoo Dianat and Axel Groß — Physik-Department T30, Technische Universität München, 85747 Garching, Germany
The dissociative adsorption of H2/Pd(110) has been studied by six-dimensional quantum dynamical calculations using a coupled-channel scheme. All hydrogen degrees of freedom have been taken into account explicitly while the substrate was kept fixed. The potential energy surface (PES) has been derived from ab initio total energy calculations. For normal incidence, the experimentally measured sticking probabilities are well-reproduced, in particular the non-monotonous behavior as a function of the kinetic energy which is indicative of the steering mechanism. We have especially focused on the role of additional parallel momentum in the adsorption process which is intimately related to the corrugation of the PES. As a consequence of the strong corrugation of the PES, we find large deviations from normal energy scaling. Furthermore, because of the anisotropy of the (110) surface, there is also a pronounced dependence of the dissociation probability on the incident azimuth of the H2 beam. In addition, we will address the dependence of the adsorption/desorption process on the rotational state of the H2 molecules. The microscopic analysis of the adsorption dynamics gives us a detailed understanding of the dissociaton of small molecules at a corrugated transition metal surface.