Reactions of Nitrogen—Hydrogen Radicals. I. NH2 Recombination in the Decomposition of Ammonia

Abstract

Photoelectric measurements of NH2 absorption as a function of time following an rf discharge pulse through ammonia are described. The extinction coefficient of the strong vibration—rotation line at 16725.40 cm—1 is found to be 1.02±0.10×103 liter mole—1 cm—1 as an upper limit. Under the proper conditions the kinetics of NH2 disappearance is second order with respect to NH2. Arguments attribute the initial stages of the observed reaction to NH2 recombination to form hydrazine. The recombination rate constant is 2.33±0.20×109 liter mole—1 sec—1 and is independent of the total pressure in the range 425 to 850 μ.