Nucleation as a local subsystem fluctuation

A nucleation theory has been advanced, in which a metastable system is considered as the sum of statistically independent subsystems. This theory provides a flexible scheme taking into account actually all initiating factors, including even a separate “weak” point in a system. In the case of a homogeneous nucleation, the difference between the classical and alternative approaches consists in the expression for the preexponential. Depending on the diameter of the critical nucleus, numerical estimates of this preexponential by the two theories differ by 0–4 orders of magnitude for a supersaturated steam and 1–5 orders of magnitude for a superheated liquid.