Model for density variation at a fluid surface

A fluid model with freely propagating longitudinal density waves is modified by the imposition of an external field. A relation between the resulting density inhomogeneity and the applied potential is obtained, depending only upon the uniform fluid pair distribution function. This is solved for a container-bounded fluid. The resulting surface density profiles for classical and zero-temperature Bose hard-sphere fluids compare very well with numerical experiments.Supported in part by U.S. ERDA, Contract No. E(11-1)-3077.Based on a talk given at Johns Hopkins Physics Colloquium, November 1974.