Molecular Dynamics (MD) simulations were performed to determine the self-diffusivity, Di,self, of H2, CO2, Ar, Kr, CH4, C2H6,
C3H8, and nC4H10 for a variety of pore concentrations within one-dimensional mesopores of 2 nm, 3 nm, 3.4 nm, 4 nm, 5.8 nm,
7.6 nm and 10 nm sizes. The MD simulated values of Di,self are compared with estimations of the commonly used Bosanquet formula
1/Di,self=1/Di,Kn+1/Ðii,fl, that combines molecule-wall and molecule-molecule interactions:, where Di,Kn is the Knudsen diffusivity,
and Ðii,fl is the self-diffusivity of species i in the fluid phase at the same molar concentration, ci, as within the mesopores.
For components with poor adsorption strength, such as H2, the MD simulated Di,self values are in good agreement with the estimations
using the Bosanquet formula for the whole range of pore concentrations. For components with strong adsorption at the pore
walls, the MD simulated values are significantly lower than the Bosanquet estimations when molecule-wall interactions are
dominant. These deviations are traceable to the failure of the Knudsen prescription of diffuse reflectance on molecule-wall
collisions, because adsorption at the pore walls introduces a bias in the molecular hops. For any given molecule, the Bosanquet
estimations tend to be increasingly accurate when the pore diameters are increased.