A perturbative density functional approach to the structure of colloidal suspension

A simple perturbative density functional approach which incorporates the three-body correlation in an approximate manner is used to study the structure of inhomogeneous as well as homogeneous colloidal suspension. The suspension is modeled as a one component fluid of charged macro particles interacting with the well known Derjaguin-Landau-Verwey-Overbeek (DLVO) potential. We have calculated the density profiles of inhomogeneous colloidal suspension in front of a highly repulsive charged wall as well as in a planar slit consisting of two parallel planar charged walls. The radial distribution function g(r) of the homogeneous suspensions of charged colloidal particles has also been calculated by making use of the well known Percus identity which relates the density distribution of an inhomogeneous fluid to the g(r) of the corresponding homogeneous fluid when the external potential responsible for the inhomogeneity is the interparticle potential itself. The calculated results on the density profiles and g(r) obtained from the present approach are found to be in closer agreement with the simulation results and show a marked improvement over those obtained from perturbative as well as nonperturbative density functional theories presented in earlier works. (C) 1998 American Institute of Physics.