SELF-CONSISTENT CLUSTER APPROACH TO THE HOMOGENEOUS KINETIC NUCLEATION THEORY

An alternative, self-consistent formulation of the homogeneous nucleat ion theory has been proposed. This approach differs from the classical Becker-Doring-Zeldovich theory in two respects: (i) evaporation rates are evaluated by referring to the stable equilibrium of a saturated v apor rather than to the constrained metastable equilibrium of a supers aturated vapor; and (ii) for the reference stable equilibrium state th e Fisher theory of condensation is used in order to obtain a self-cons istent definition of the free-energy barrier for 1-cluster formation, where 1 is the number of molecules in the cluster. A comparison of the expressions for the nucleation rate and critical cluster size with th e corresponding classical expressions has been made for the different parts of the phase diagram (temperature-supersaturation) and the domai n where both theories are close has been found. Predictions of the pre sent theory have been compared with the experimental results on nuclea tion of n-nonane for the three sets of experiments (diffusion cloud ch amber, fast-expansion cloud chamber, and two-piston cloud chamber). It has been shown that the present theory has a much better agreement wi th experimental results for n-nonane than the classical theory.