Arthur J. M. Yang

TL;DR: In this article, a molecular theory of surface tension is developed for a liquid-gas interface of a one component system and the Helmholtz free energy is obtained from a rigorous expansion in powers of derivatives of density ρ and is minimized by the calculus of variations.

TL;DR: The van der Waals theory of surface tensions is generalized to multicomponent systems in this paper, where the local free energy density consists of a "local equilibrium" free energy (i.e., equilibrium free energy of a uniform mixture having species densities equal to the local species density) plus a quadratic form in the gradients of the local densities.

TL;DR: In this article, a one component system, a liquid drop in equilibrium with its vapor, is studied in the discussion of the stability of a heterogeneous system with a spherical interface.

TL;DR: In this paper, the van der Waals theory of surface tensions in the presence of gravity is discussed in detail and the physical two-phase solution in the gravitational field is shown to exist and is unique.

TL;DR: In this paper, the Gibbs free energy for a one component fluid system with a spherical interface is derived by following a reversible path at constant T, P, and N. The process is generalized to discuss the free energies for a liquid drop containing a nucleus and for a multicomponent system containing more than one droplet.