Cai, Q.Biggs, M.Seaton, N.2010-01-182010-01-182008Physical Chemistry Chemical Physics, 2008; 10(18):2519-25271463-90761463-9084http://hdl.handle.net/2440/55509The effect of the pore wall model on the self-diffusion coefficient and transport diffusivity predicted for methane in graphitic slit pores by equilibrium molecular dynamics (EMD) and non-equilibrium MD (NEMD) is investigated. Three pore wall models are compared—a structured wall and a smooth (specular) wall, both with a thermostat applied to the fluid to maintain the desired temperature, and a structured wall combined with the diffuse thermalizing scattering algorithm of MacElroy and Boyle (Chem. Eng. J., 1999, 74, 85). Pore sizes ranging between 7 and 35 and five pressures in the range of 1–40 bar are considered. The diffuse thermalizing wall yields incorrect self-diffusion coefficients and transport diffusivities for the graphitic slit pore model and should not be used. Surprisingly, the smooth specular wall gives self-diffusion coefficients inline with those obtained using the structured wall, indicating that this computationally much faster wall can be used for studying this phenomenon provided the fluid-wall interactions are somewhat weaker than the fluid–fluid interactions. The structured wall is required, however, if the transport diffusivity is of interest.enJournal article002009269810.1039/b716648f2-s2.0-4304909717937503