The green bands which are associated with the 5577 A oxygen line for oxygen and argon mixtures have been obtained with an ozonizer discharge tube. Nitrogen was found to greatly enhance the intensity of the green if the discharge tube was maintained at the temperature of liquid air. Spectrograms with a plate factor of 1.9 A/mm partially resolve the rotational structure of the overlapping vibrational bands. A 20 ${\mathrm{cm}}^{-1\mathrm{}}$ difference appears between several bands. It is assumed that this spectrum results from loosely bound molecular states which may be represented by $\mathrm{A}\left({}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}\right)\mathrm{O}\left({}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}\right)$ and $\mathrm{A}\left({}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}\right)\mathrm{O}\left({}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}\right)$. There are no bands associated with the 2972 A line. The 5577 A line and associated bands have been observed in a dc arc through 3 atmospheres of commercial argon.

A green glow is found to dominate the spectrum of an oxygen and nitrogen mixture if the discharge is maintained at - 192°C. This spectrum consists of the 5577 A line, a continuum, and a few diffuse bands.

• Received 18 November 1957

DOI:https://doi.org/10.1103/PhysRev.109.2026