Structure of Lennard-Jones fluids in a confined system

A density-functional perturbation approximation. which is based both on the second-order perturbation theory of liquids and on the contact value theor em for the pore, has been proposed to study the structural properties of a Lennard-Jones fluid in a slit pore. The advantage of the present approximat ion is that it is computationally simpler than the original density-functio nal approximation based on the second-order perturbation theory of liquids. The calculated result for the confined Lennard-Jones fluids is better than those of a density-functional theory based on the so-called mean-field app roximation and is in good agreement with the computer simulation. However, its accuracy slightly deteriorates with increasing bulk density.