Multiparticle simulation for morphological transitions in diffusion-limited aggregation

The two models based on multiparticle diffusion-limited aggregation (DLA) are presented to study the morphological changes in diffusive systems. The first model, which takes into account the propagation of cations from the dissolving anode, is proposed for the Hecker effect, which appears in recent experiments of electrochemical deposition. The second model with two components, in which the one component is condensable and the other component is not, is presented to investigate the effect of an incondensable gas on the morphology of DLA. Computer simulation is performed for the deposition process on the plate in two dimensions. In the first model, it is shown that the morphological change of deposits occurs from a less dense structure at the inner region to a more dense structure at the outer region. In the second model, it is found that the morphological transitions appear from the dense structure, through the bay pattern, to the needle structure, with increasing concentration of incondensable gas.