FREE-ENERGY EXPRESSIONS FOR A SPHERICAL INTERFACE

The free energy is analysed of a spherical interface generated in a fl uid described by a local free energy density functional that features square-gradient and square-laplacian terms. The bulk, the surface tens ion and the bending rigidity terms are investigated, and the position is found for the dividing surface that satisfies the generalized Lapla ce equation that incorporates bending terms. The results agree with th ose obtained previously from the general expression for the stress ten ser of an interface of arbitrary shape (Romero-Rochin, V., Varea, C., and Robledo, A., 1991, Phys. Rev. A, 44, 8417; 1993, Phys. Rev. E, 46, 1600). Also, when a comparison is made between spherical and planar i nterfaces the expressions obtained are those derived by Gompper, G., a nd Zschocke, S. (1991, Europhys. Lett., 18, 731) and by Blokhuis, E. M ., and Bedeaux, D. (1993, Molec, Phys., 80, 705). These expressions co rrespond to the length of Tolman and to similar higher-order correctio n terms.