The dynamics of the diffusion-limited model of cluster-cluster aggregation is investigated in two and three dimensions by studying the temporal evolution of the cluster-size distribution ns(t), which is the number of clusters of size s at time t. In a recent study it was shown that the results of the two-dimensional simulations for mass-independent diffusivity can be well represented by a dynamic-scaling function of the form ns(t) s-2f(s/tz), where f(x) is a scaling function with a power-law behavior for small x, namely f(x)x for x 1 and f(x) 1 for x 1. In this paper we extend the calculations of the cluster-size distribution to three dimensions and to the case of the cluster diffusivity depending on the size of the clusters. The diffusion constant of a cluster of size s is assumed to be proportional to s. The overall behavior of ns(t) and the exponents and z have been determined for a set of values of. We find that the results are consistent with the scaling theory, and the exponents in ns(t) depend continuously on. Moreover, there is a critical value of [c(d=2)-(1/4), c(d=3)-1/2] at which the shape of the cluster-size distribution crosses over from a monotonically decreasing function to a bell-shaped curve which can be described by the above scaling form for ns(t), but with a scaling function f(x) different from f(x).
ASJC Scopus subject areas
- Condensed Matter Physics