Upper limit for the generation of N2O from reaction of O-2(A(3)Sigma(+)(u)) and N-2

Evidence from several sources suggest possible in situ production of N2O in the stratosphere. Considering that solar photoabsorption provides a large stratospheric source of O-2(A (3) Sigma(u)(+)), and since vibrational levels of upsilon greater than or equal to 6 are primarily removed by N-2, the O-2(A (3) Sigma(u)(+)) + N-2 system is studied to determine whether it is an atmospherically significant N2O source. Using 243-250 nm photoexcitation to produce vibrationally excited O-2(A (3) Sigma(u)(+), upsilon = 7-10), and frequency modulation diode laser spectroscopy as the detector of N2O, we examine the products generated in a closed cell. We thereby set an upper limit of 0.002% on the N2O yield for the process, and conclude that stratospheric N2O production by this route is not significant compared to existing groundbased sources. The stability of N2O in an N2O-O-3-N-2 mixture subjected to prolonged 245 nm radiation is also studied. For low levels of O-3 (10 ppm) and N2O (40-90 ppb), no loss of N2O is observed.