1ST-LAYER FORMATION IN BALLISTIC DEPOSITION OF SPHERICAL-PARTICLES - KINETICS AND STRUCTURE

We present a computer simulation and theoretical study of a ballistic deposition process in which spheres are incident on a planar surface. Each incoming sphere follows a path of steepest descent which may invo lve rolling over the surface of preadsorbed spheres. All particles rea ching a stable, elevated position are removed. The frequency of the va rious rolling mechanisms are evaluated as a function of coverage. The addition mechanism generates clusters of connected spheres by accretio n and coalescence. We evaluate the dependence of the cluster size dist ribution and coalescence probability on coverage. Various peaks in the radial distribution function of the deposited layer provide a signatu re for the deposition mechanism. The asymptotic approach to saturation is shown to be of the form theta(infinity) - theta(t) is-proportional -to exp[-(4/pi)S(m)t]/t2, where S(m) = square-root 3/2 is the smallest possible target area. The expression is shown to be consistent with t he simulation results. Interpolants, which accurately describe the tim e-dependent coverage over the entire coverage range, are developed bas ed on the exact expressions for the asymptotic and low coverage kineti cs.