Metal surface adsorbed clusters: Structure and dynamics

Extensive numerical simulation are reported for the structure and dynamics of large clusters on metal(1 0 0) surfaces. Different types of perimeter hopping processes makes center-of-mass of the cluster to follow a a random walk trajectory. A d iffusion coefficient D for the whole cluster can be defined as lim⁡t→∞D(t), with D(t)=〈d2〉/(4t) and d the displacement of the center-of-mass from its initial position. The dependence of the diffusion coefficient on those perimeter hopping processes can be analyzed in detail, since the relations between different rates for the processes are explicitly considered as parameters. The value of the diffusion coefficient D behaves as D∼N−α, while different values for the exponent α have been proposed depending on which diffusion mechanism is considered to facilitate the movement of the cluster.