SIMULATION OF CLUSTER GROWTH USING A LATTICE-GAS MODEL

Lattice gas models have been used to study the growth of icosahedral and fcc clusters. The simulations include adsorption, desorption, and diffusion of atoms to the nearest and next nearest lattice sites. A general survey of cluster growth is given from a diffusion dominated low pressure case to the adsorption dominated high pressure case. In general, clusters seem to grow monotonically without spending longer times at any cluster size. Compact clusters are observed only close to the limits of low and high pressures, and the growth is controlled either by diffusion or adsorption, accordingly. Both of these mechanisms can produce layer by layer type growth. When the layer by layer growth takes place only along (111) surfaces in fcc clusters, a reglar pattern is obtained in the abundance spectrum. This has the same frequency as the octahedral growth, even though the individual clusters are not perfect octahedra. © 1994 The American Physical Society.