Developments in the hard sphere model for self-diffusion and shear viscosity. I: Methane as a model hard sphere fluid

摘要: Abstract Examination of shear viscosity (η) and self-diffusion coefficient ( D ) data for liquid methane, together with equivalent hard sphere diameters (σ ϱ derived from densities along the solid-liquid coexistence curve, is used to show that Stokes-Einstein equation in hydrodynamic slip limit obeyed only at very high densities. The product ησ / kT differs significantly both low values obtained molecular dynamics (MD) simulations a fluid. Values η/η E (η = Enskog dense fluid viscosity) place those MD simulations, gave expected A η (translational-rotational coupling factor) nitrogen > 1), (within uncertainty experimental on which calculation based) liquefied rare gases 1) temperatures within 20–25% critical temperatures. Apparent departures smooth behaviour, approaching triple points, are accounted by assumption less packing liquids transition than