Mass-Spectrometric Study of the Reactions of O Atoms with NO and NO2

The reactions of O atoms with NO and NO2 have been studied using a mass spectrometer to directly measure the O-atom partial pressure. The results obtained are as follows: NO+O+M→NO2+M, k1(M is N2)=(1.44±0.20)×1015exp (1930±100/RT) cc2 mole−2·sec−1;NO2+O→NO+O2, k2=(1.95±0.61)×1013exp (−1060±200/RT) cc mole−1·sec−1. These reactions are discussed in terms of the general mechanism O+XO⇌ lim BA[OXO]*+M→ lim CXO2+M→ lim DX+O2→ lim EXO2+hv. The rates of the elementary reaction steps have been calculated from the over-all rate constants and previous results on the isotopic exchange rates of 18O with O2, NO, and NO2.