Adsorption of a diatomic molecular fluid into random porous media - art. no. 051501

Structural and thermodynamic properties of a homonuclear hard dumbbell flui d adsorbed into a disordered hard sphere matrix are studied by means of int egral equation techniques and computer simulation. In particular, we have r ewritten the replica Ornstein-Zernike equations to deal with orientational degrees of freedom and we have solved them in two different approaches: the hypernetted chain equation and a semiempirical extension of Verlet's appro ximation. We have also derived direct expressions to calculate the chemical potential in these approximations. Comparison with grand canonical Monte C arlo results shows that both theoretical treatments describe adequately the physical behavior of the system, Verlet's approach being, however, clearly superior in accordance with previous findings for equilibrated hard core m ixtures.