Growth probability distribution in irregular fractal-like crystal growth of ammonium chloride

Scaling structures of the growth probability distribution are studied for a two dimensionally grown irregular fractal-like dendrite of ammonium chloride, whose fractal dimension coincides with that of diffusion-limited aggregation. Three different kinds of probability measure are brought into the analysis, i.e., growth site area, normal growth velocity obtained from two successive pictures, and the potential gradient calculated from the Laplace equation. Generalized dimensions D(q) with q=-,0,1, are in good agreement with those obtained by the recent off-lattice diffusion-limited-aggregation simulation and theory.