Density functional theory: X-ray reflectivity studies of pure fluid liquid/vapour interfaces

摘要: Although there are numerous model independent methods for the extraction of a density profile from X-ray reflectivity data, many systems fundamental limitations to uniqueness profiles so determined owing limited range scattering data and nature inverse transformation. Based on functional theory (DFT) inhomogeneous fluids we liquid/vapour interface some pure simple liquids (Ar, N2, Kr, CCl4). Attractive contributions Helmholtz free energy treated by mean-field approximation (MF). Both local (LDA) smoothed (SDA) applied repulsive reference system described hard sphere equation state. A cut-off shifted Lennard-Jones potential divided according Weeks–Chandler–Andersen (WCA)-prescription is used as intermolecular interaction force model. The parameters were modelling saturated liquid densities fluid. Computed theoretical predict specular reflectivities. Capillary waves models Braslau etal. (Phys. Rev. A, 1998, 38, 2457), Evans (Mol. Phys., 1981, 42, 1169) Meunier (J. Phys. (Paris), 1987, 48, 1819) adopted approximate these both reflectivities surface tension. We propose parameter procedure based intrinsic interfacial thickness calculate terms. agreement predicted with experimental good in case where terms included. Similarly tension calculated part plus due capillary wave roughening. All calculations exclusively densities.