The ultravioletA3Sgr;u+mdash;X3Sgr;gmdash;oxygen bands have been observed in emission from greenishhyphen;white ``air'' afterglows containing 95ndash;98 nitrogen and 2 to 5 oxygen. The afterglows were excited by an electrodeless rf oscillator and examined with a grating spectrograph having anf/2 camera and a dispersion of 30 A/mm. The mechanism of excitation of these bands in the afterglow may be either the reaction N+O3rarr;NO+O2or the reaction N+NO2rarr;N2+O2. A comparison of the afterglow spectrogram with an ultraviolet night airglow spectrogram shows that bands arising from higher vibrational levels are more intense in the airglow than in the afterglow. Collisional dehyphen;excitation can account for the lower vibrational temperature in the laboratory. The atomic nitrogenhyphen;ozone reaction also may occur in the chemosphere between 60 and 90 km and may contribute to the excitation of the night airglow Herzberg bands. The atomic nitrogen at this level could come from daylight predissociation of NO and N2and from the twilight dissociative recombination of ionized NO.
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