A simple sticking probability model is used for deducing a kernel capable t
o describe the kinetics of computer-simulated irreversible aggregation proc
esses. Not only the diffusion- and reaction-limited aggregation regimes wer
e fitted but also the whole transition region. The deduced kernel establish
es lambda = 0 for the entire range of sticking probabilities and helps to u
nderstand how irreversible cluster-cluster aggregation works.