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 55.56: Poster
Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F
Phases with long-range order observed in the interaction of silver with the Re(1010) surface. — •Viktor Scherf1, Christian Pauls1, Lyria Messahel1,2, and Klaus Christmann1 — 1Institut für Chemie und Biochemie der FU Berlin, D-14195 Berlin — 2University of Sciences and Technology H. Boumediène, U.S.T.H.B., Faculty of Chemistry, B.P.32, El-Alia 16111, Bab Ezzouar, Algiers, Algeria.
We have studied the interaction of silver with the Re(1010) surface in UHV in the temperature range between 300 and 800 K by means of low-energy and medium-energy electron diffraction (LEED and MEED) as well as with temperature-programmed thermal desorption (TPD). Deposition of Ag from submonolayer to multilayer coverages was accomplished in small coverage increments; the monolayer concentration was calibrated using MEED and examined using LEED-(I,V) calculations. Short annealing at 800 K ensured thermodynamic equilibrium of the Ag phases formed, since it is not until 950 K that Ag desorbs in noticeable amounts. Within the submonolayer coverage regime the following ordered LEED phases could be observed with increasing Ag coverage: c(2x2); p(1x4); p(1x5), and (1x1), whereby all phases turn out to be uniquely correlated with temperature and surface coverage. We develop structure models of the Ag phases and discuss and compare our data with recent studies of Au on Re(1010) and Ag on Ru(1010) surfaces.