Gas-liquid nucleation in partially miscible systems: Free-energy surfaces and structures of nuclei from density functional calculations

Gas-liquid nucleation in partially miscible Lennard-Jones systems is studied using the density functional theory in a perturbation approach. Nucleation properties are examined in a symmetric and an asymmetric mixture. Both systems are shown to form two kinds of mixed critical nuclei in one vapor composition. Spherically symmetric clusters with a phase separated structure are found in the asymmetric mixture; these are shown to correspond to local maxima of the Gibbs free-energy surface. A classical calculation also suggests that the cylindrically symmetric clusters found in earlier studies have higher formation energies than the spherical nuclei in the same vapor. (C) 1999 American Institute of Physics. [S0021-9606(99)51936-3].