NUCLEATION THEORY AND DYMAMICS OF FIRST-ORDER PHASE TRANSITIONS NEAR A CRITICAL POINT

Abstract
A brief review of nucleation theory and its problems is given. Main emphasis is on nucleation close to the critical point of liquid-gas systems or liquid liquid mixtures, and the interpretation of recent experiments in these systems. It is shown that critical slowing down leads to considerable enhancement of the relative undercooling at the limit of metastability close to the critical point. The role of pre-exponential factors on the nucleation rate is discussed, and scaling laws for nucleation near the critical point are derived. Computer simulations of the lattice gas model are used to show that the one-cluster-coordinate theory is sufficient even close to the critical point and that the classical "capillarity approximation" underestimates the energy barriers even at fairly low temperatures.