1. 0 2030 2040 2050 2060 2070 2080 2090 2100 2110
2. Hz data 9 second average multichannel analyzer (OMA) interfaced to a grating monochromator. The OMAis a Roper Scientific Model7410-0003, witha liquid-nitrogen-cooled 1024-elementInGaAsdetector array. The arrayis mounted inthe exitplane ofa Jobin-Yvon0.32 m monochromator equipped witha 600 line/mmgrating blazed at 1 µmwavelength. The emissioniscollected fromthe flowreactor byanoptical fiber mounted on the monochromator entrance slit. Examplesofthe observed emissionspectra for discharge-generated O2(a)andO2(b)areshowninFigures9and10, respectively. The spectral resolutionofthe rotational envelopes ofthe spectra is sufficientfor determinations ofrotational temperatures bya spectral fittinganalysis. Inaddition, the spectral range provided bythe grating permitssimultaneousobservationsofemission from O2(a)at1.27µmandI*at1.315µm.
3. DetectionofO2(a)byemissionspectroscopyis somewhat problematic owing to the need to (1) perform absolute radiometric calibrations(see below), and (2) assume a value for the band-integrated Einstein coefficient for the aÆX transition. Atpresent, values reportedinthe literature for the aÆXEinstein coefficient range over a factor of~2, withhighly credible investigationsat both extremes.18-21Recent absorptionmeasurementsat high spectralresolution give 2.19 x10-4s-1,20,21howeveraprevious determination19of1.47x10-4s-1haslongbeen accepted bythe atmospheric aeronomycommunity. We believe that concurrent measurementsofthe ratio [O2(a)]/[O2](Eqs.(1)and(2)),[O2]inthereaction zone, and the absolute emissionintensityofO2(aÆX), canbe applied to the determinationofthe Einstein coefficient ofthe aÆX transition. This workisin development.