Semiempirical van der Waals/Cahn-Hilliard theory: Size dependence of the Tolman length

The interfacial density profiles, pressure tensor, and Tolman-length ST are determined for the critical droplets of nonane in the framework of the sem iempirical van der Waals/Cahn-Hilliard theory. It is shown that the Tolman' s length is strongly size dependent, and tends to a negative value for larg e drops; indicating that Tolman's approximation for the curvature: dependen ce of the interfacial free-energy gamma approximate to gamma(infinity)/(1 2 delta(T,eq)/R) based on the equilibrium values delta(T,eq), and gamma(in finity), is inaccurate for typical liquid nuclei. (C) 1998 American Institu te of Physics. [S0021-9606(98)52946-7].