Thermal diffusion factors for binary gas systems: Ar-N₂, Ar-CO₂, He-H₂, He-N₂O, Kr-N₂O and He-NH₃

Abstract

The thermal diffusion factors for six binary systems are measured in a two-bulb metal apparatus as a function of temperature and composition. The values are compared with the available values in the literature, wherever possible, and with the predictions of the Chapman-Enskog kinetic theory involving elastic collisions. The contribution of dipole and quadrupole moments of polar gases to the thermal diffusion factor is estimated according to the theories developed by Mason and co-workers. In general, the thermal diffusion data involving polyatomic and polar gases are not well represented by the available theories, and generation of reliable data may provide considerable guidance and much needed clues for the development of an accurate but tractable theory. A possible explanation of the minima and maxima observed in the thermal diffusion data is advanced.