DENSITY-FUNCTIONAL THEORY OF LIQUID-CRYSTAL SURFACES

We develop a density-functional theory based on weighted density forma lism to describe the surfaces of liquid crystals. The expression for t he surface free energy is written in terms of order parameters charact erizing the nature and amount of ordering in the interface and the str uctural parameters which involve the spherical harmonic coefficients o f the direct pair correlation function of an effective isotropic fluid the density of which is determined using a criterion of the weighted density-functional formalism. We report preliminory results of our cal culations for nematic/vapour and nematic/isotropic liquid interfaces.