Abstract :
Nucleation near the gas-liquid critical point sensitively depends on whether the pressure or the volume is fixed. Upon decompression to a constant pressure, bulk nucleation can well be induced from a gas state, whereas phase separation from a liquid state is more easily triggered in the thermal diffusion layer near the boundary. In this case bulk nucleation in a metastable gas is described by the classical Lifshitz-Slyozov theory. On the other hand, upon cooling of the boundary temperature under the fixed-volume condition, bulk nucleation can be realized in a liquid and a modified Lifshitz-Slyozov theory follows. However, if a gas is cooled from the boundary at a fixed volume, phase separation readily occurs in the thermal diffusion layer, apparently suggesting no metastability in a gas in agreement with previous experiments
