Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 17: Adsorption II
O 17.4: Vortrag
Dienstag, 28. März 2006, 12:00–12:15, TRE Phys
Adsorption and C 1s NEXAFS Spectra of Three Phenylpropenes on Cu(111) — •C. Kolczewski1, F. J. Williams2, R. L. Cropley2, R. M. Lambert2, and Klaus Hermann1 — 1Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany — 2Department of Chemistry, University of Cambridge, Cambridge CB2 1 EW, UK
In this study we present equilibrium geometries of trans-methylstyrene, α-methylstyrene and allylbenzene adsorbed on Cu(111) obtained from density functional theory (DFT) calculations using Cu73-C9H10 clusters. All molecules are found to adsorb with their phenyl ring lying flat on the surface. However, the position of the side chain varies: allylbenzene adsorbs with its propenyl chain pointing away from the surface whereas for trans-methylstyrene and α-methylstyrene the side chains are closer to the surface but differ in their relative arrangement of C=C bonds and allylic hydrogens. These results can explain the different epoxidation rates measured for the three molecules by simple geometric arguments. The calculated geometries are also used to evaluate theoretical angle resolved C 1s NEXAFS spectra which can be compared with experimental spectra and yield excellent agreement. This confirms the adsorption geometries obtained in the present study and underlines the geometric interpretation of the epoxidation behavior of the phenylpropenes.