Kinetics of Nitrogen Atom Recombination

The rate of recombination of nitrogen atoms in the nitrogen afterglow has been measured in a flow system using NO as a titrant and determining the NO content continuously by mass spectrometer. Above about 3 mm of mercury the reaction is predominantly homogeneous and third order. The rate constant, 5.7×1015 cc2 mole—2 sec—1, is independent of temperature in the interval studied (195–450°K). The rate is reduced by substituting helium or argon for N2 as the third body, the ratios of the third-order rate constants with these third bodies being about the same as those for recombination of iodine and bromine atoms. Below about 3 mm of mercury a pseudo-first-order wall recombination becomes important. The recombination coefficient was found to be 1.6×10—5 on a glass wall that undoubtedly was partly poisoned by water.