EMISSION SPECTRA OF ATMOSPHERIC SPECIES

Abstract

The technique of Fourier spectroscopy has been applied to survey infrared spectra of atmospheric molecules in the 1800 to $7800\;cm^{-1}$ region. Emission spectra are obtained from electronic discharges operating under similar conditions as those that exist in the upper atmosphere, with typical pressures in the 0.2 to 0.3 Torr range. The discharge column, 1 meter in diameter and 12 meters long, is triple-passed, resulting in an equivalent optical path of 36 meters--sufficient for producing good S/N. Spectra of discharges using $N_{2}, O_{2}, CO_{2}$, He and air have been obtained with a spectral resolution up to $0.1\;cm^{-1}$. The spectra of the CO fundamental and $CO_{2}\;4.3\;\mu m$ band predominate in 1800 to $2300\;cm^{-1}$, while the molecular and atomic transitions of other species axe identified in high $cm^{-1}$ region. Discussion will include analysis of the observed bands and the instrumentation problems.