Anomalous behaviour of the diffusion coefficient in interacting adsorbates

    Authors

    S. Zayzoune; M. Mazroui; Y. Boughaleb;A. Kara

    Abbreviated Journal Title

    Surf. Sci.

    Keywords

    Surface diffusion; Correlations; Langevin simulation; Tracer diffusion; STRONG-COLLISION MODEL; BROWNIAN PARTICLES; SURFACE-DIFFUSION; LONG; JUMPS; DYNAMICS; SYSTEMS; CHAOS; NOISE; Chemistry, Physical; Physics, Condensed Matter

    Abstract

    Langevin simulations provide an effective way to study collective effects of Brownian particles immersed in a two-dimensional periodic potential. In this paper, we concentrate essentially on the behaviour of the tracer (D(Tr)) and collective diffusion coefficients (D(C)) as function of friction (Gamma). Our simulations show that in the high friction limit, the two physical quantities D(Tr) and D(C) present qualitatively the same behaviour, for both coupled and decoupled substrate potentials. However, for the low friction regime, and especially for the coupled potential case, an anomalous diffusion behaviour is found where D(Tr) similar to Gamma(-sigma Tr) and D(C) similar to Gamma(-sigma C), with sigma(Tr) < sigma(C) < 1. We also found that in the case of weak dynamical coupling between the adparticles and the substrate, the exponents are not universal and rather depend on the potentials. Moreover, changes in the inter-particle potentials may reverse the behaviour to a normal one. (C) 2009 Elsevier B.V. All rights reserved.

    Journal Title

    Surface Science

    Volume

    603

    Issue/Number

    20

    Publication Date

    1-1-2009

    Document Type

    Article

    Language

    English

    First Page

    3126

    Last Page

    3130

    WOS Identifier

    WOS:000271179600014

    ISSN

    0039-6028

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