We report a high-resolution, small-angle x-ray study of aggregated gold colloids over the range 0.0003 to 0.08 ${\mathrm{\AA }}^{-1\mathrm{}}$. We are able to fit our data with a simple model that correctly accounts for nonfractal short-range order with a crossover to long-range fractal correlations. This provides new information on the structure of real aggregates, and new insight into the aggregation processes which lead to their formation.

• Received 19 February 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.595