IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS3-ThP

Paper SS3-ThP6
Mechanism of O@sub 2@ Ejection from Pt(111) at 100K Induced by Gas-phase D Atom

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Surface Reactions Poster Session
Presenter: J. Lee, Seoul National University, Korea
Authors: J.-Y. Kim, Seoul National University, Korea
J.S. Choi, Seoul National University, Korea
S.J. Lee, Seoul National University, Korea
J. Lee, Seoul National University, Korea
Correspondent: Click to Email
Rettner and Lee@footnote 1@ have shown that the gas-phase H(D) atom incident on an O2-adsorbed Pt(111) surface at 85K induces prompt desorption of O2 with a translational energy well in excess of the surface temperature. To elucidate the mechanism of this nonthermal desorption of O2, we have performed detailed kinetic studies using a D atom beam generated in a hot tungsten capillary tube at 1900K. Real-time monitoring of the gas-phase desorption products and post-reaction TPD measurements have been made with a QMS to find out 1) O2 and D2O desorb simultaneously with different kinetics, 2) the initial desorption rate of O2 is proportional to the O2 coverage, 3) at submonolayer O2 coverages, the O2 desorption rate increases with time following a step-like initial jump, which is more pronounced at a lower coverage, and 4) post-reaction TPD spectra show multiple D2O desorption peaks with increasing D atom exposure. Based on these observations, we conclude that O2 desorption occurs by site displacement of primary as well as secondary hot D atoms, which competes with D2O formation reaction. @FootnoteText@@footnote 1@ C. T. Rettner and J. Lee, J. Chem. Phys. 101 (1994) 10185.