KINETICS OF CLUSTER GROWTH BY AGGREGATION

The classical problem of the coalescence of isolated species to produce growing clusters/colloids/polymers by successive statistical encounters having the same rate constant, is revisited using numerical simulation for a maximum nuclearity value of a few 10(3) units. The evolution with time of the abundance of clusters of a given nuclearity and of the total population, and the distribution of sizes at a given time are obtained and compared with models from the literature. A remarkable feature of these curves is that they exhibit parity effects for the nuclearity, even clusters being systematically more abundant than odd ones. For easier comparison with experiments, some simulated curves are presented in the form of an approximated analytical expression: kinetics of the total population, and of the monomer,dimer and higher oligomers populations, amplitudes at the maximum and delay for the maximum as functions of the nuclearity, size distribution at a given time. The validity of the approximations is discussed.