Lennard-Jones fluids in cavities

Static and dynamic properties of Lennard-Jones particle in spherical cavities of molecular dimensions are studied by molecular dynamics (MD) simulation. The local density is a function of the radial coordinate; a layered density profile is reproduced by the iterative solution of an approximate BGY equation. The pair correlation function exhibits a broadened first-neighbor peak and a second-neighbor peak which is shifted inward from its location in the homogeneous fluid. The viscosity, as measured by the relaxation of a rotor in the cavity, is a function of the cavity radius and may actually decrease as the cavity radius decreases. This qualitative trend is reversed when the smooth cavity is replaced by a cavity with rough, molecular walls.