Fractal Ag-aggregates on silicone oil surfaces

The growth Process of large fractal aggregates formed by diffusion and rota tion of silver clusters on silicone oil surfaces is investigated. Our resul ts indicate that the silver clusters rotate randomly on the liquid substrat es and the mean square angle displacement < (Delta theta)(2)> and time diff erence at satisfy the generalized Einstein relation < (Delta theta)(2) > = 4D(theta)Delta t.The random rotation coefficient D-theta scales with the cl uster size S as D-theta proportional to S (-gamma theta), where gamma(theta ) =2.4 +/- 0.3. The dependence of the fractal dimension of the aggregates o n the deposition rate and aggregate time is also presented.