Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 33: Methods: Electronic structure theory II
O 33.2: Vortrag
Mittwoch, 25. März 2009, 10:45–11:00, SCH A316
Density functional study of the adsorption of Aspirin on (001) surface of α-quartz — •Afshin Abbasi1, 2, Ebrahim Nadimi1, 2, Philipp Plänitz2, and Christian Radehaus2, 3 — 1Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz, Germany — 2GWT-TUD GmbH - Geschäftsstelle Chemnitz, Annaberger Str. 240, 09125 Chemnitz, Germany — 3Fakultät für Elektrotechnik und Informationstechnik, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
In this study the adsorption geometry of aspirin molecule on the hydroxylated (001) α-quartz surface has been investigated using DFT calculation. The optimized adsorption geometry indicates that both adsorbed molecule and substrate are strongly deformed. Strong hydrogen bonding between aspirin and surface hydroxyls, leads to the breaking of original hydroxyl-hydroxyl Hydrogen bonds on the surface as well as the covalent bond between aspirin acidic oxygen and hydrogen (O-H). In this case new hydrogen bonds on the hydroxylated (001) α-quartz surface are resulted which significantly differ from ones on the clean surface. The 1.11 eV adsorption energy reveals that the interaction of aspirin with α-quartz is an exothermic chemical interaction. These observations have been used to explain previous experimental results, which had studied the stability of aspirin in the aspirin-silica solid mixtures.