AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS-ThA

Paper SS-ThA6
Photoinduced Reaction Dynamics of Halocarbon Adlayers on the Fe3O4 (111)-(2x2) Selvedge of Fe2O3 (0001)

Thursday, November 6, 2003, 3:40 pm, Room 328

Session: Oxide Reactions and Catalysis
Presenter: G.G. Totir, Columbia University
Authors: G.G. Totir, Columbia University
Y. Le, Columbia University
R.M. Osgood, Jr., Columbia University
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Electron transfer reactions on surfaces play a key role in electrocatalysis and in photoinduced processes in surface-adsorbate systems. More recently, interest in understanding the reactivity of iron oxides toward halogenated hydrocarbons has been stimulated by applications in catalysis and environmental decontamination procedures. We used time-of-flight (TOF) and temperature programmed desorption (TPD) to study the electron transfer reaction dynamics and photochemistry of halocarbons on surface reconstructed single crystal hematite, Fe2O3 (0001). For example, TPD spectra recorded at various coverages of methyl iodide adsorbed at 100 K on the magnetite, Fe3O4, termination of single crystal hematite, indicate a rich surface chemistry, with multiple desorption events, similar to results previously obtained for other adsorbates on the same surface. Furthermore, angle-resolved TOF results for monolayer coverage of methyl iodide on Fe3O4 (111)-(2x2) indicated that the methyl fragments produced from dissociative electron attachment were ejected at an angle of ~ 0o with respect to the surface normal. Post-irradiation desorption spectra for methyl iodide and carbon tetrachloride on the magnetite surface, and results discussing adsorbate orientation and coverage dependence will be presented.