Density Functional Theory of Inhomogeneous Liquids IV. Squared-gradient approximation and Classical Nucleation Theory

摘要

The Squared-Gradient approximation to the Modified-Core Van der Waals densityfunctional theory model is developed. A simple, explicit expression for the SGAcoefficient involving only the bulk equation of state and the interactionpotential is given. The model is solved for planar interfaces and sphericalclusters and is shown to be quantitatively accurate in comparisons to computersimulations. An approximate technique for solving the SGA based onpiecewise-linear density profiles is introduced and is shown to give reasonablezeroth-order approximations to the numerical solution of the model. Thepiecewise-linear models of spherical clusters are shown to be a naturalextension of Classical Nucleation Theory and serve to clarify some of thenon-classical effects previously observed in liquid-vapor nucleation.Nucleation pathways are investigated using both constrained energy-minimizationand steepest-descent techniques.