title: Density fluctuations and the structure of a nonuniform hard sphere fluid.
abstract: We derive an exact equation for density changes induced by a general external field that corrects the hydrostatic approximation where the local value of the field is adsorbed into a modified chemical potential. Using linear response theory to relate density changes self-consistently in different regions of space, we arrive at an integral equation for a hard sphere fluid that is exact in the limit of a slowly varying field or at low density and reduces to the accurate Percus-Yevick equation for a hard core field. This and related equations give accurate results for a wide variety of fields.
authors.affiliation: Institute for Physical Science and Technology, University of Maryland, College Park 20742, USA.
authors.forename: K
authors.initials: K
authors.lastname: Katsov
authors.forename: J D
authors.initials: JD
authors.lastname: Weeks