Isotope effects in the interaction of hydrogen and deuterium with a rhodium (110) surface |
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Authors: | K. Christmann M. Ehsasi |
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Affiliation: | (1) Institut für Physikalische Chemie, Freie Universität, Takustrasse 3, D-1000 Berlin 33;(2) Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4–6, D-1000 Berlin 33 |
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Abstract: | The adsorption of H2 and D2 on a Rh (110) surface at 100 K leads to a sequence of ordered phases, among others 1×2 phases atH=0.5 and atH=1.5 which likely involve a partial surface reconstruction consisting of a small perpendicular displacement of Rh surface atoms. The structure of the adsorbate phases is strongly correlated with the binding energy of the adsorbed phases. Three H (D) binding states (1,2 and) are populated at saturation as determined by thermal desorption spectroscopy (TDS). Whereas the peak temperature of the state is invariant with the hydrogen isotope, the D 1 state appears at a 8 Klower and theD 2 state at a 5 Khigher temperature than the respective H states. Generally the D phases exhibit a better long-range order than the H phases. The rate of adsorption is identical for the first three adsorbed phases but D2 adsorbs appreciably faster in the 1×2–3H and the final l×1–2H phases.Zero point energy effects as well as a H coverage dependent local interaction model could account for the observed effects. |
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Keywords: | 82.20Tr 82.65Jv 82.65Nz |
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