Translational energy release in the recombinative desorption of H2 from Ag(111) |
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Authors: | M. J. Murphy and A. Hodgson |
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Affiliation: | Surface Science Research Centre, University of Liverpool, Liverpool, L69 3BX, UK |
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Abstract: | We have investigated the recombinative desorption of H2 from Ag(111) using (2 + 1) REMPI to detect the desorbing molecules. We describe a method for determining the energy released into translational motion normal to the surface over a wide range of surface temperatures. This was achieved by using a weak electric field to disperse the ions, in contrast to the usual field-free method. Calibration and analysis methods are discussed and energy distributions P(E) are reported for H2 (v=0). Desorption from a 295 K surface shows only a single low-energy peak (), whereas the translational energy release is bimodal for desorption from a 580 K surface, with mean desorption energies of approximately 140 meV and 1 eV for the two pathways. Sticking functions are calculated using detailed balance, revealing a large dependence on surface temperature. |
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Keywords: | Adsorption kinetics Hydrogen Low index single crystal surfaces Resonance enhanced multiphoton ionization mass spectroscopy (REMPI/MS) Silver Sticking |
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