Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)
O 41.9: Poster
Dienstag, 23. März 2010, 18:30–21:00, Poster B1
HR-EELS-study of the adsorption of propionic acid on clean and H2O saturated Si(001) surfaces — •Bochra Boughaled Ellakhmissi1, Miriam Lange1, Stefan Kubsky2, Francois Rochet3, and Ulrich Köhler1 — 1Experimentalphysik IV, Ruhr-Universität Bochum, Germany — 2Synchrotron Soleil, St. Aubin (Paris), France — 3Laboratoire de Chimie Physique Matière et Rayonnement, Univ. P. et M. Curie, Paris, France
High resolution electron energy loss (HR-EELS) spectroscopy is used to study the reaction of propanoic acid (CH3-CH2-COOH) with the clean and the hydroxylated Si(001) surface. The results are compared to photoemission data. For the adsorption on the clean Si(001)-2x1 surface the results point to the simultaneous presence of different adsorption geometries, monodentate and bidentate. To circumvent the inhomogeneity caused by multiple adsorption geometries, in a second set of experiments the silicon surface was first modified by the adsorption of water leading to a grafting layer of Si-H and Si-O-H. During the reaction of the hydroxylated surface with propionic acid the strongly diminished O-H stretching mode together with the appearance of the C-H mode clearly shows a reaction of the acid with the water layer. Further information is gained by replacing the H2O grafting layer by a D2O layer to distinguish hydrogen (deuterium) related vibrational excitations of the grafting layers from the ones coming from the carboxylic acid. The vibrational data are consistent with the selective adsorption of the propionic acid with the Si-O-H groups via an esterification reaction in a monodentate geometry.