Anisotropic diffusion of a fluid confined to different geometries at the nanoscale

Self-diffusion coefficients of a fluid confined to slab and cylindrical geometries at the nanoscale with varying widths have been studied by considering different density profiles. The average second frequency sum rule of a velocity autocorrelation function in a direction parallel and perpendicular to the wall has been evaluated. It is found that confinement to the nano length scale results in anisotropic diffusion and the diffusion coefficient is directly dependent on the width of the channel and the density profile.