In analogy to recent results on nonuniversal roughening in surface growth [Lam and Sander, Phys. Rev. Lett. 69, 3338 (1992)], we propose a variant of diffusion-limited aggregation (DLA) in which the radii of the particles are chosen from a power-law distribution. For very broad distributions, the huge particles dominate and the fractal dimension is calculated exactly using a scaling theory. For narrower distributions, it crosses back to DLA. We simulated 1200 clusters containing up to 200 000 particles. The fractal dimensions obtained are in reasonable agreement with our theory. This variant of DLA might have relevance to the cluster-cluster aggregation model.

• Received 20 December 1993

DOI:https://doi.org/10.1103/PhysRevE.49.R1788