Prediction of homogeneous nucleation free-energy change from the cell model of liquids

Abstract

The free-energy change of cluster formation in gas-phase homogeneous nucleation and the cluster partition functions are studied based on the cell model of liquids. We provide a new molecular-level theory that is applicable in the larger cluster size range where liquid-like properties begin to emerge and a cluster surface is present. The microcluster surface tension can be appropriately defined. A microscopic expression for the surface tension variation with cluster size is obtained and the calculated result is compared with that predicted from the Tolman approach. The cluster rotational contribution to the free-energy change is shown to become insignificant for liquid-like clusters. The energy changes of cluster formation from the classical capillary approximation, the Lothe-Pound theory, and the atomistic theory are compared with that of the present theory.