Simulations on "powder" Samples for Better Agreement with Macroscopic Measurements

Different experimental measurement techniques give widely differing values for diffusivity (D_s) and activation energy (E_a) for the same sample. Values from molecular dynamics simulations agree with quasi-elastic neutron scattering measurements and not with those obtained from macroscopic techniques, such as uptake or zero length column chromatography. We report molecular dynamics simulations on different zeolite samples with intercrystalline space along 0-, 1-, 2-, and 3-dimensions. The results on n-hexane in zeolite NaY samples with intercrystalline space along three-dimensions exhibit values of D_s and E_a in excellent agreement with macroscopic techniques, demonstrating the importance of "powder" samples in simulations.