Vibrational Relaxation of O2 in O2−D2 Mixtures and of H2 and D2

Abstract

Shock-tube interferometry has been used to observe vibrational relaxation of O2 in O2+D2 mixtures. From 300° to 850°K the present shock tube and previous ultrasonic relaxation times in atmosphere seconds are given by log10(pτO2−D2)=27.3T−13−8.35. Above 1500°K the relaxation time of O2 is further shortened due to effects of chemical reaction or possibly to a resonant-energy exchange with the more rapidly excited D2. Hydrogen vibrational relaxation is too rapid to be resolved, yielding pτH2<2×10−6 atm·sec for T = 1400°K. The vibrational relaxation of deuterium appears to be more complex than other diatoms studied and is not yet understood. However, it is observed that pτD2<6×10−6atm·sec at T = 1400°K.