Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)
O 55.36: Poster
Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F
Adsorption of benzene on the Si(001)-(2×1) and the SiC(001)-(3×2) surfaces – a comparative theoretical study — •Jürgen Wieferink, Peter Krüger, and Johannes Pollmann — Institut für Festkörpertheorie, Universität Münster
We have investigated the adsorption of benzene (C6H6) on (001) surfaces of Si and SiC employing the generalized-gradient approximation of density functional theory together with norm-conserving pseudopotentials. Using the quadratic string method [1] we have explored reaction pathways to possible final adsorption states.
At Si(001)-(2×1), we find C6H6 to initially adsorb via electrophilic addition in a butterfly configuration by binding two opposite (1,4) carbon atoms to the silicon atoms of one surface dimer. The energetically most favorable tight-bridge structure can then be reached by the formation of two additional bonds between the (2,3) carbon atoms and an adjacent silicon dimer [2].
At SiC(001)-(3×2), the silicon dimers are further apart from each other. As a result, this surface cannot feature bridging geometries and is thus expected to generate an ordered monolayer of butterfly benzene, where each molecule exhibits two π-bonds that are available for further reactions. An energetically more favorable dissociated adsorption structure is also discussed and shown to be kinetically unreachable. Finally, the electronic structure of the optimized geometries is examined and discussed.
[1] S. K. Burger, W. Yang, J. Chem. Phys. 124, 054109 (2006)
[2] J.-Y. Lee, J.-H. Cho, Phys. Rev. B 72, 235317 (2005)