Diffusion coefficient and interatomic potential of He–Ar at high temperatures.

Measurements of the mutual diffusion coefficient D12 for the He/Ar gaseous system have been extended to 2050 K, approximately 600 deg beyond any previous work. The results, obtained in a tungsten–tantalum–hafnium alloy (‘‘T-111’’) two-bulb cell, are in excellent agreement with previous studies in the 200–1400 K range. An equation is presented which has been fitted to all available published D12 results. An HFD-B interatomic potential is proposed which accurately predicts D12 within accepted experimental uncertainties. [ABSTRACT FROM AUTHOR]