Intermolecular Forces: Thermal Diffusion and Diffusion in Ar-Kr

Abstract

Thermal diffusion and diffusion measurements on Ar-85Kr, made by the two-bulb method, are reported for the temperature range 77-600°K. In part of the temperature range there is an unexplained discrepancy between our thermal diffusion data and those of Grew and Mundy, making it no longer clear that the thermal diffusion factor has a positive minimum. However, it is confirmed, by the use of a specially constructed thermal diffusion column, that the thermal diffusion factor is positive between 77 and 90°K. The ordinary diffusion coefficients are in excellent agreement with other work. Notwithstanding the thermal diffusion discrepancy, it is clear that the exp-6, Kihara core, and Morse potential models are not entirely satisfactory.