Shock tube study of DF vibrational relaxation

Abstract

The vibrational relaxation of DF behind incident shock waves in the temperature range 800–4000° K has been studied by monitoring the 3.5-μm infrared emission. Relaxation times reduced to standard pressure were obtained for mixtures containing 1%–10% DF in Ar and for mixtures containing N2, H2, and F atoms. These data were used for calculation of the relaxation times of DF due to these various gases. The relaxation data can be summarized by P τDF–DF=1.4× 10−3exp (63.7/T1/3) μsec·atm (above 2000°K), P τDF–Ar=7.1× 10−3exp (128.6/T1/3) μsec·atm, P τDF–H2=1.9× 10−2exp (35/T1/3) μsec·atm. The values of P τDF–N2 fell between those for Ar and D2. The deactivation rate of DF by F was measured to be 1.5× 1013cc/mole·sec. The measurements were compared to the predictions of several theories of vibration-to-translation and vibration-to-rotation energy transfer.