VIBRATIONAL-RELAXATION OF UF6 - ULTRASONIC MEASUREMENTS IN MIXTURES WITH AR AND N2

Ultrasonic attenuation has been measured in neat UF6 and in mixtures of 5% and 10% UF6 in Ar and N2 at 273 and 323 K. In all cases a single relaxation process was observed and attributed to relaxation of the total UF6 vibrational energy. Isothermal relaxation times were in the range (4-17) × 10-9 atms. The vibrational relaxation rate inferred for UF6-N2 collisions shows a slight negative temperature dependence, while the rates inferred for UF 6-UF6 and UF6-Ar collisions are virtually independent of temperature over the range of these experiments. In this range, Ar and N2 are slightly less efficient collision partners (by factors of ∼1.5-3.0) than UF6 itself. © 1979 American Institute of Physics.