The DLCA-RLCA transition arising in 2D-aggregation: simulations and mean field theory

A sticking probability model based on the average cluster lifetime is emplo yed for deducing a kernel capable to describe the kinetics of computer simu lated irreversible aggregation processes in two dimensions. The deduced ker nel describes not only the time evolution of the cluster size distribution for diffusion limited aggregation (DLCA) and reaction limited aggregation ( RLCA) but also for the entire transition region between both regimes. The m odel predicts a crossover to diffusion limited cluster aggregation for all sticking probabilities at long aggregation times. The time needed for reach ing the DLCA limit increases for decreasing sticking probability.