A measurement of the rate of the reaction N + H + M → NH + M

The combination reaction between N and H atoms has been studied in a flow system by mixing H atoms produced by thermal dissociation of H 2 with active nitrogen produced by a microwave discharge. Relative N atom concentrations were determined from the intensity of the yellow nitrogen afterglow. Absolute N and H atom concentrations were measured by EPR absorption spectroscopy. Absolute N atom concentrations were also determined by titration with NO. Upper and lower limits of 6.4 ± 1.5 × 10 −32 and 3.1 ± 1.0 × 10 −32 cm 6 molecule −2 sec −1 were determined for the rate constant.