Molecular fluids in an external field

Abstract

A functional perturbation theory for molecular fluids in an external field is developed. The theory reduces to the Tarazona-Navascués (1982, Molec. Phys., 47, 145) and Haile et al., (1976, J. chem. Phys., 64, 1852) theories under certain approximations and in the absence of any external potential. The theory is applied to axial molecules using spherical harmonic expansions for the density, the anisotropic interactions and the external potential. An explicit integral equation for the harmonic coefficients of the density is obtained. A hard sphere fluid with anisotropic interactions near a wall has been the molecular model chosen to obtain numerical results. An orientation layer-structure in phase with the isotropic structure has been found.