Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.9: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
Interaction of Acetic Acid with Solid Water: A Study with IR Reflection-Absorption Spectroscopy (RAIRS) and Electron Spectroscopies (MIES; UPS) — •Stephan Bahr and Volker Kempter — Institut für Physik und Physikalische Technologien, Technische Universität Clausthal, 38678 Clausthal-Zellerfeld, Germany
The interaction of cyclic dimers of acetic acid, CH3COOH, with solid water (D2O) at 120K on polycrystalline Ag was investigated. Metastable Impact Electron Spectroscopy (MIES) and Ultraviolet Photoelectron Spectroscopy UPS(HeII) were utilized to obtain information on the electronic structure of the outermost surface. Infrared Reflection–Absorption spectroscopy (RAIRS) allowed for the identification of the AA species, and provides information on their hydration and the water–induced fragmentation.
The AA species quickly saturate the water OD dangling bonds at the ice surface, even before the first AA layer becomes saturated. For less than 0.3ML coverage the cyclic dimers break up into monomers and linear dimers under the influence of their interaction with the D2O molecules. For coverages >0.3ML strong lateral interaction between AA monomers increases the linear dimer fraction. The second and following adlayers formed at 120K consist of cyclic dimers, mainly. The results will be compared to theoretical predictions [1,2].
[1] Picaud, S.; Hoang, P.; Peybernès, N.; LeCalvé, S.; Mirabel, P. J. Chem. Phys. 2005, 122, 194707. [2] Allouche, A.; Bahr, S. J. Phys. Chem. B 2006, 110, 8640.