O2 Dissociation Rates O2‐Ar Mixtures

Experimental measurements of the O2 dissociation rate in shock‐heated oxygen‐argon mixtures were obtained with the ultraviolet light absorption technique described in the preceding article. The dissociation rate constant kAr for the reaction O2+Ar→O+O+Ar can be fit over the temperature range from 3400 °K to 7500 °K by the theoretical formula kAr = C(D/RT)n−12 exp(−D/RT), where C = 6.0×101±20% cc/mole‐sec and n = 1.5±0.2. 0 = 5.116 ev is the oxygen dissociation energy; R is the gas constant; and T is the temperature. This result is compared with the classical collision theory and the theories of Wigner and Keck. The rates for the dissociation of O2 by O and O2 were also determined; compared to the argon rate constant kO≈25kAr, kO2⪅3kAr Our experimental results are compared with those of Byron and Matthews. The relaxation times for dissociation and vibration are observed to be comparable at about 8000 °K. The experimental data indicate that the dissociation rate above 8000 °K is at least a factor of two les...