Density dependent potentials: Structure and thermodynamics

Local density dependent potentials constitute a family of many body potentials which have been recently introduced in mesoscopic modeling of simple and complex fluids. We construct a field theory for these potentials and calculate the structure factor of the fluid through a saddle point expansion. We propose also an integral equation for local density potentials which shows quantitative agreement both for the correlation functions and thermodynamic properties of such potentials, even close to binodals where the simpler saddle point approximation fails. Contrary to the limitations of global density dependent potentials, there is no ambiguity in the expression of thermodynamics quantities such as the pressure.