ABSTRACT
The debt owed to J.van der Waals for revealing the essence of fluid behavior in his famous analysis of the binding energy and excluded volume mechanisms [1, 2] is widely recognized as enormous. Less known is the fact that van der Waals also extended his theory to nonuniform fluids [3]. This work was a beginning of the development of socalled density functional theories which have only recently gained prominence in both quantum chem-istry [4, 5] and statistical mechanics [6, 7]. Here we shall review the origin of the generalized van der Waals (GvdW) theory with the aim to show that the remarkable accuracy of simple mechanistic analysis applies also to a wide range of nonuniform fluid phenomena such as adsorption, surface tension, and electrolyte screening. Thus the traditional equa-tion of state of van der Waals as well as the DebyeHückel and Poisson-Boltzmann theories of electrolyte screening are simple special cases of the GvdW theory which unify and considerably extend these well-known traditional approximations to account, in particular, for nonlocal entropy and short-range packing structure.
