The kinetic theory of diffusion and thermal diffusion in adsorbed gases

The derivation of general expressions for the surface diffusion and thermal diffusion coefficient is presented on the basis of the Chapman-Enskog solution of the kinetic equation for an adsorbed gas. The numerical calculations of these coefficients for 36A-40A mixtures adsorbed on the graphite surface are described for intermolecular interaction potentials proposed by Sinagoğlu and Pitzer and by Barker and Everett. The method elaborated by Smith and Munn is adapted for numerical calculations on surface binary collisions. The results obtained are compared with those appropriate to transport properties of ordinary three-dimensional gases.