Surface corrugation effects: molecular ethane adsorption dynamics on rigid adsorbate-covered surfaces of Pt(111)

SURFACE SCIENCE

卷:395

Article

Stinnett, JA ; Weaver, JF ; Madix, RJ

关键词: adsorption kinetics;    alkanes;    atom-solid interactions;    catalysis;    computer simulations;    low index single crystal surfaces;    molecular dynamics;    platinum;   

DOI  :  10.1016/S0039-6028(97)00555-4

来源: Elsevier

【 摘 要 】

Angular distributions of ethane molecules scattered from sulfur-and ethylidyne-covered Pt(111), and clean Pt(111) were measured at surface temperatures of 135 and 210 K. Direct-inelastic scattering from the adsorbate-covered surfaces displays dramatic, broad back-scattering of ethane, while the clean surface produces maximum scattering intensity near the specular angle. Stochastic trajectory simulations for ethane on Pt(111)-S employing a potential developed from the trapping of ethane on Pt(111) gives a quantitative account of the broad angular distributions and the measured initial trapping probabilities at all energies and polar angles of incidence studied. The simulations clearly suggest facile interconversion of the incident parallel and perpendicular momenta of ethane upon the first collision with Pt(111)-S, which enhances trapping relative to clean Pt(111) at normal incidence, but increases scattering at more glancing angles, The simulations indicate the trapping probabilities for ethane on Pt(111)-S are determined to within 208 by the fate of the first bounce. Analysis of a large number of trajectories illustrates that at all angles of incidence, ethane is steered by the corrugation of the surface toward the bare platinum regions, producing both the broad angular distributions of the scattered species and the weak dependence of the trapping probability on the angle of incidence. (C) 1998 Elsevier Science B.V.

【 授权许可】

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