Influence of particle size on diffusion-limited aggregation

The influence of particle size on diffusion-limited aggregation (DLA) has b een investigated, by computer simulations. For DLA clusters consisting of t wo kinds of particles with different sizes, when large particles are in the minority, die patterns of clusters appear asymmetrical and nonuniform, and their fractal dimensions D-f increase compared with one-component DLA. Wit h increasing size of large particles, D-f increases. This increase can be a ttributed to two reasons: one is that large particles become new growth cen ters; the other is the big masses of large particles. As the concentration ratio x(n) of large particles increases, D-f will reach a maximum value D-f m and then decrease. When x(n), exceeds a certain value, the morphology and D-f of the two-component DLA clusters are similar to those of ore-componen t DLA clusters. [S1063-651X(99)05510-5].