Vibrational relaxation in polyatomic molecules: SF6

摘要

Vibrational relaxation in mixtures of 5percnt;, 10percnt;, and 25percnt; SF6in Ar has been studied behind incident shock waves over the temperature range 450ndash;1050 K by timehyphen;resolved measurement of postshock density gradients using a laser beam deflection technique. Short extrapolation of the results obtained yields excellent agreement with ultrasonic data in the range 200ndash;420 K. Contrary to original reports, results from infrared fluorescence and double resonance measurements at 300 K are shown to be in disagreement with the ultrasonic data. A discussion of relaxation behavior in polyatomic molecules under differing conditions of departure from equilibrium shows that such a discrepancy is to be expected in general.