INTERFACIAL SUPERSATURATION, SECONDARY NUCLEATION, AND CRYSTAL-GROWTH

A theory describing the source of nuclei in secondary nucleation is presented and used to rationalize experimental data from the literature, some of which had appeared to be conflicting. The theory rests on a model in which an adsorption layer consisting of clusters of growth units of varying size is formed on the surface of growing crystals. The existence of the layer is related to the two-resistance model of crystal growth; by varying system conditions, the relative importance of the two resistances is altered and thereby changes the interfacial supersaturation even though overall supersaturation remains constant. Interfacial supersaturation and contact energy determine kinetics in a system dominated by contact nucleation.