A kinetic approach to the theory of nucleation in gases

Abstract

A theory of nucleation in gases is developed in which the rate of evaporation of the molecules from the cluster is calculated on the basis of a diffusion equation in the energy space. In contrast to the classical theory of nucleation, the theory does not employ macroscopic thermodynamics. Numerical calculations were performed by assuming an intermolecular potential which combines the dispersive attraction with the rigid core repulsion. The predictions of the theory are consistent with the classical theory in the limit of small supersaturations, i.e., for large critical clusters. For small critical clusters the present theory provides much higher rates of nucleation than the classical one. This difference can be attributed to the use of the macroscopic surface tension in the classical theory, which overpredicts the surface energy of small clusters, and consequently provides lower values for the nucleation rate. The theoretical results are compared with experimental data for nucleation of supersaturated vapors of lower alcohols carried in argon.