CLUSTER-CLUSTER AGGREGATION AND CALCULATED SAXS PATTERNS - APPLICATION TO CONCENTRATION-DEPENDENCE OF FRACTAL PARAMETERS

Two new computer simulation programs are presented, GRASP and DALAI. G RASP is an off-lattice implementation of the cluster-cluster aggregati on model, including diffusion- and reaction-limited aggregation as wel l as aggregate reorganization. The aggregate systems produced by GRASP are characterized by DALAI, which calculates the x-ray scattering pat tern using a CPU-efficient simplified version of the Debye formula. We describe the scope and potential of the two programs and we show how they can be used together to follow the time evolution of aggregation in large systems. We also present results of DLCA calculations for rep resentative 2D and a series of 3D systems in the volume concentration range 0.25-30.0% with the purpose of investigating the influence of co ncentration on fractal parameters.