Scaling properties of the critical nucleus in classical and molecular-based theories of vapor-liquid nucleation

Scaling relations are developed for the number g* of molecules in the critical nucleus and the nucleation barrier height W*. Density functional (DF) calculations for vapor-liquid nucleation confirm these relations and show systematic departure of the ratio W*/g*Delta mu from its classical value of 1/2 with increasing difference Delta mu in the chemical potential between the supersaturated vapor and bulk condensed phase. Discrepancies between classical and DF nucleation theories and between the classical theory and experiment are interpreted using these results.