UPPER LIMIT FOR THE GENERATION OF N2O FROM REACTION OF O-2(A(3)SIGMA(-2()(U)) AND N)

Evidence from several sources suggest possible in situ production of N 2O in the stratosphere. Considering that solar photoabsorption provide s a large stratospheric source of O-2(A (3) Sigma(u)(+)), and since vi brational levels of upsilon greater than or equal to 6 are primarily r emoved by N-2, the O-2(A (3) Sigma(u)(+)) + N-2 system is studied to d etermine whether it is an atmospherically significant N2O source. Usin g 243-250 nm photoexcitation to produce vibrationally excited O-2(A (3 ) Sigma(u)(+), upsilon = 7-10), and frequency modulation diode laser s pectroscopy 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 y ield for the process, and conclude that stratospheric N2O production b y this route is not significant compared to existing groundbased sourc es. The stability of N2O in an N2O-O-3-N-2 mixture subjected to prolon ged 245 nm radiation is also studied. For low levels of O-3 (10 ppm) a nd N2O (40-90 ppb), no loss of N2O is observed.