Kinetics of Adsorption on Stepped Surfaces and the Determination of Surface Diffusion Constants

Abstract

Nitrogen adsorption on stepped W(110) surfaces is examined to illustrate a theory of surface kinetics. Experimental findings by Besocke et al. have shown that nitrogen chemisorbs dissociatively only at the step corner sites of a W(110) surface. Thus the rate of dissociation reveals the mobility of nitrogen and its interaction with the surface. Using continuous-time-random-walk theory, we obtain the probability that molecules reach the step corner sites as a function of time. A kinetic model of nitrogen dissociation is proposed to calculate a coverage function that is in good agreement with experiment. The surface diffusion constant of nitrogen molecules is obtained and is in accordance with previous observations that nitrogen molecules are first weakly physisorbed on the W(110) terrace. Finally, the coverage functions for different step densities are predicted.

Department(s)

Electrical and Computer Engineering

Keywords and Phrases

Dissociation; Lattices; Periodic Traps; Random Walks; Surface Diffusions

International Standard Serial Number (ISSN)

0022-4715

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1983 Kluwer Academic Publishers, All rights reserved.

Publication Date

01 Feb 1983

Link to Full Text

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