  The fundamental measure approach to classical density functional theory has
been shown to be a powerful tool to predict various thermodynamic properties of
hard-sphere systems. We employ this approach to determine not only one-particle
densities but also two-particle correlations in binary and six-component
mixtures of hard spheres in the vicinity of a hard wall. The broken isotropy
enables us to carefully test a large variety of theoretically predicted
two-particle features by quantitatively comparing them to the results of
Brownian dynamics simulations. Specifically, we determine and compare the
one-particle density, the total correlation functions, their contact values,
and the force distributions acting on a particle. For this purpose, we follow
the compressibility route and theoretically calculate the direct correlation
functions by taking functional derivatives. We usually observe an excellent
agreement between theory and simulations, except for small deviations in cases
where local crystal-like order sets in. Our results set the course for further
investigations on the consistency of functionals as well as for structural
analysis on, e.g., the primitive model. In addition, we demonstrate that due to
the suppression of local crystallization, the predictions of six-component
mixtures are better than those in bidisperse or monodisperse systems. Finally,
we are confident that our results of the structural modulations induced by the
wall lead to a deeper understanding of ordering in anisotropic systems in
general, the onset of heterogeneous crystallization, caging effects, and glassy
dynamics close to a wall, as well as structural properties in systems with
confinement.
