Chemiluminescence of nitric oxide: The NO (C2[Pi]-A2[Sigma]+) rate constant

A rocket borne scanning 1/4-m spectrometer was used to observe the night airglow between 1900 and 2300 A at a resolution of 15 A. An attitude control system oriented the payload horizontally near apogee (150 km) and pointed the field of view to the north and parallel with the terminator. Progressions from the [delta](0, v") and [gamma](0, 0) band system of nitric oxide were observed. The observations of the [delta]-bands and [gamma]-bands are consistent with the relative intensities produced in the preassociation of ground state atomic oxygen and nitrogen. An observation of the v' = 0, [var epsilon]-band progression is suggested and is consistent with the presence of a resonance fluorescence contribution near apogee. The A2[Sigma]+ (upper level of the [gamma]-bands) can only be populated by cascade from the C2[pi] state (upper level of the [gamma]-bands) in the preassociation reaction. In the absence of quenching of the A2[Sigma]+ state, the emission rate of the [gamma]-bands can be used as a measure of the C-A transition and thus to deduce the branching ratio to the A2[Sigma]+ state. This branching ratio is estimated to be 0.21+/-0.04.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24388/1/0000658.pd