NONCLASSICAL NUCLEATION THEORY - AN EXACTLY SOLUBLE MODEL

Classical nucleation theory relies on the capillarity approximation: the assumption that the free energy of a small cluster of a new phase can be described by a bulk free energy difference (from thermodynamics) plus a surface term (with effects of curvature neglected). We have used density functional theory to develop a nonclassical theory, one which allows the order parameters to vary through the cluster in order to give the lowest possible barrier to nucleation. This approach has been applied to crystallization of liquids from the melt and to condensation of liquids from the vapor, and shows significant deviations from classical nucleation theory. A simple, exactly soluble model will be introduced and used to explore the limits of validity of classical nucleation theory.