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Statistical mechanical models for dissociative adsorption of O-2 on metal(100) surfaces with blocking, steering, and funneling

TitleStatistical mechanical models for dissociative adsorption of O-2 on metal(100) surfaces with blocking, steering, and funneling
Publication TypeJournal Article
Year of Publication2014
AuthorsEvans, JW, Liu, DJ
JournalJournal of Chemical Physics
Volume140
Pagination194704
Date Published05
Type of ArticleArticle
ISBN Number0021-9606
Accession NumberWOS:000336832700033
Keywordschemisorption, co oxidation, film growth, kinetics, lattice-gas, oxygen, pd(100), random sequential adsorption, square lattice, sticking probabilities
Abstract

We develop statistical mechanical models amenable to analytic treatment for the dissociative adsorption of O-2 at hollow sites on fcc(100) metal surfaces. The models incorporate exclusion of nearest-neighbor pairs of adsorbed O. However, corresponding simple site-blocking models, where adsorption requires a large ensemble of available sites, exhibit an anomalously fast initial decrease in sticking. Thus, in addition to blocking, our models also incorporate more facile adsorption via orientational steering and funneling dynamics (features supported by ab initio Molecular Dynamics studies). Behavior for equilibrated adlayers is distinct from those with finite adspecies mobility. We focus on the low-temperature limited-mobility regime where analysis of the associated master equations readily produces exact results for both short-and long-time behavior. Kinetic Monte Carlo simulation is also utilized to provide a more complete picture of behavior. These models capture both the initial decrease and the saturation of the experimentally observed sticking versus coverage, as well as features of non-equilibrium adlayer ordering as assessed by surface-sensitive diffraction. (C) 2014 AIP Publishing LLC.

DOI10.1063/1.4875813
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Chemical Physics