Restructuring effects in irreversible deposition of spheres on a plane.

Abstract

We present an irreversible-deposition model which encompasses as special cases both random sequential adsorption (RSA) and simple ballistic deposition (BD). In this deposition process, hard spheres are added sequentially to a plane along vertical straight-line trajectories initiated at random positions. Multilayer formation is prevented. The spheres can adsorb on the plane either by direct deposition or by following the path of steepest descent on previously deposited particles. The ratio of the rates of the two mechanisms is characterized by a parameter which is equal to 0 for RSA and 1 for simple BD. Using liquid-state methods, we obtain a third-order density expansion for the pair-density function and for the rate of deposition. We consider also the kinetics of the process and we show, by computer simulation and theoretical arguments, that the system reaches its saturation state exponentially. Finally, we discuss several interpolation formulas that incorporate the exact small- and large-time behavior.