The Effect of Pressure on the Chemiluminescent Spectrum of Oxygen Atoms and Nitric Oxide
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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As another approach to establishing the mechanism of the chemiluminescent reaction between oxygen atoms and nitric oxide, the effect of pressure on the spectrum has been investigated. The oxygen atoms were generated by a microwave discharge, and mixed with nitric oxide in a two-stage system where the pressure could be varied from 1.0 to 0.005 torr. Spectra obtained at pressures below 0.5 torr all show a shift towards the blue the magnitude of the shift is roughly proportional to the decrease in pressure below 0.5 torr. This shift is almost identical with that observed in the fluorescence of NO2. Adding either argon or sulfur hexafluoride to the mixture at low pressures does not change the spectrum but at around 1 torr, SF6 causes a shift similar to a decrease in pressure. These results are shown to be consistent with a multi-step mechanism involving the formation, stabilization, quenching, and vibrational de-excitation of one excited electronic state.
- Inorganic Chemistry