surface diffusion of k-mers in one-dimensional systems

F. BULNES; A. J. RAMIREZ-PASTOR; G. ZGRABLICH

SURFACE SCIENCE

Elsevier

Lugar: Amsterdam; Año: 2007 vol. 601 p. 569 - 577

0039-6028

The surface di.usion of interacting k-mers is studied both through analytical and Monte Carlo simulation methods in one-dimensional systems. Adsorption isotherms, jump di.usion coeffcients and collective diffusion coeffcients are obtained for attractive and repulsive k-mers, showing a variety of behaviors as a function of the size of particles, k. The following main results are found: (a) diffusion coeffcients increase with k for non-interacting particles; (b) for fixed k, diffusion coeffcients increase as the interaction energy increases from negative (attractive) to positive (repulsive) values; (c) for attractive interactions diffusion coeffcients increase with k in the whole range of coverage; (d) for repulsive interactions diffusion coeffcients decrease with k up to moderately high coverage and increase with k at high coverage. Results are rationalized in terms of the behavior of the vacancy probability distribution.