Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: Metal substrates: Adsorption of O / H and inorganic molecules I
O 12.4: Vortrag
Montag, 14. März 2011, 15:45–16:00, WIL A317
Non-adiabatic Effects during the Dissociative Adsorption of O2 at Ag(111)? A first-principles Divide & Conquer Study — •Itziar Goikoetxea1,2, Juan Beltrán1, Jörg Meyer1,3, Maite Alducin2, Iñaki Juaristi2, and Karsten Reuter1,3 — 1Fritz-Haber-Institut der Max-Planck- Gesellschaft, Berlin, Germany — 2Centro de Fisica de Materiales, San Sebastian, Spain — 3Technische Universität München, Germany
A predictive materials science modeling based on microscopic understanding requires a thorough knowledge of all underlying elementary processes at the atomic scale. The adsorption of individual oxygen molecules at metal surfaces is one example -crucially relevant not only but in particular in heterogeneous catalysis. Recent work on the dissociative adsorption of O2 at Al(111) has severely chal- lenged its prevalent understanding: A non-adiabatic transition of the molecular spin state favored by low density of states at the Fermi- level has been proposed to reconcile experimental observations with ab-initio theory [1]. Consequently, coinage metal surfaces might be fur- ther good candiates for such effects. With this motivation, we have used a first-principles based divide and conquer approach to study O2 on Ag(111). Experimental observables like e.g. (initial) sticking and scat- tering turn out to be semi-quantitatively reproduced with adiabatic dynamics already. Finally, the emerging picture for the interaction of oxygen molecules with this surface is compared to the low-dimensional model originally proposed by Kleyn et al. [2]. [1] J. Behler et al., Phys. Rev. Lett. 94, 036104 (2005). [2] A. W. Kleyn et al., Surf. Sci. 363, 29 (1996).