Local structure and density fluctuations in confined fluids

Spatial confinement modifies the microscopic structure of dense fluids, thereby inducing for example structural forces between the confining walls. However, confinement also modifies the fluids' density fluctuations, resulting in more elusive but equally important effects. In this brief review it is shown that both of these phenomena are naturally analyzed using the confined fluid's pair densities, which have recently become also experimentally accessible. Two particular topics are discussed, namely, the mechanisms of oscillatory density profiles and ensuing solvation forces in dense confined fluids as well as the behavior of liquids in solvophobic confinement.