Diffusion of small clusters on metal (100) surfaces: Exact master-equationanalysis for lattice-gas models

Citation
Jr. Sanchez et Jw. Evans, Diffusion of small clusters on metal (100) surfaces: Exact master-equationanalysis for lattice-gas models, PHYS REV B, 59(4), 1999, pp. 3224-3233
Citations number
23
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B-CONDENSED MATTER
ISSN journal
01631829 → ACNP
Volume
59
Issue
4
Year of publication
1999
Pages
3224 - 3233
Database
ISI
SICI code
0163-1829(19990115)59:4<3224:DOSCOM>2.0.ZU;2-X
Abstract
Exact results are presented for the surface diffusion of small two-dimensio nal clusters, the constituent atoms of which are commensurate with a square lattice of adsorption sites. Cluster motion is due to the hopping of atoms along the cluster perimeter with various rates. We apply the formalism of Titulaer and Deutch [J. Chem. Phys. 77, 472 (1982)], which describes evolut ion in reciprocal space via a linear master equation with dimension equal t o the number of cluster configurations. We focus on the regime of rapid hop ping of atoms along straight close-packed edges, where certain subsets of c onfigurations cycle rapidly between each other. Each such subset is treated as a single quasiconfiguration, thereby reducing the dimension of the evol ution equation, simplifying the analysis, and elucidating limiting behavior . We also discuss the influence of concerted atom motions on the diffusion of tetramers and larger clusters. [S0163-1829(99)05704-5].