Further details on particle inception and growth in premixed flames

On this basis, it has been hypothesized that two graphitization processes occur during the first stages of soot inception: a slight increase of in plane aromatic islands in primary particles and the formation of aromatic plane stacks in coagulated primary particles. This second type of coagulating-graphitization process explains the closure of the band gap observed in the grown particles respect to the primary ones, and hence the change of optical properties, towards the typical values observed in soot.