Fractal geometries in decay models

Abstract
Results of computer studies of the geometries produced by two distinct decay models are present. While one of the models (diffusion-limited decay) results in compact clusters, the other (random-walk decay) produces ramified clusters with the Hausdorf dimension (df) equal to 1.75+or-0.03 and 2.34+or-0.03 in two and three dimensions respectively. The spectral dimension (ds) is found to be 1.68+or-0.13 and 1.31+or-0.04 for d=2 and 3.