Direct measurement of the diffusion coefficients of hydrogen atoms in six gases

Abstract

The diffusion coefficients of hydrogen atoms have been directly measured at 295 K in six gases (He, Ne, Ar, H₂, N₂ and CO₂) using the Taylor dispersion technique. The precision obtained is an improvement of that on previous values. The results are also used to test various intermolecular potentials. Predictions from very simple models such as hard spheres and the Lennard-Jones (12,6) potential obtained from combination rules are found to be poor particularly for CO₂. Predictions from potentials derived from molecular-beams studies and ab initio calculations are better, but are ca. 10 % lower than the experimental data on average.