Cluster-cluster aggregation and calculated SAXS patterns: application to concentration dependence of fractal parameters

Abstract

Two new computer simulation programs are presented, GRASP and DALAI. GRASP is an off-lattice implementation of the cluster-cluster aggregation model, including diffusion and reaction-limited aggregation as well as aggregate reorganization. The aggregate systems produced by GRASP are characterized by DALAI, which calculates the X-ray scattering pattern 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 processes in large systems. We also present results of DLCA calculations for representative 2D and a series of 3D systems in the volume concentration range 0.25-30.0% with the purpose of investigating the influence of concentration on fractal parameters.