화학공학소재연구정보센터
Journal of Chemical Physics, Vol.106, No.7, 2752-2761, 1997
Structure of Inhomogeneous Dipolar Fluids - A Density-Functional Approach
A density functional approach is developed for inhomogeneous dipolar fluids consisting of dipolar hard spheres in presence of external electric fields. The theory is applied to two systems, viz. a confined fluid between two planar charged walls where the field is uniform, and also a fluid where the dipoles are subjected to a radial field due to a uniformly charged hard sphere ion at the centre. A nonperturbative weighted density approximation is employed to incorporate the effect of short range hard sphere-like correlations while the long-range effects are obtained perturbatively. The nonuniform density is expanded in terms of spherical harmonics and the correlation function used as input corresponds to the mean spherical approximation. In the case of planar geometry, the calculated density and polarization profiles are quite comparable with the available simulation and other results. In the presence of the radial field, the polarization exhibits oscillations showing a clear variation of the effective dielectric constant within the interface. This theory also gives an approximate estimate of the static solvation energy of an ion in a dipolar solvent.