On the Schumann-Runge O₂Bands emitted at Atmospheric Pressure

The Schumann-Runge bands of O 2 , previously analysed in the region 3100-4200 A. and photographed below 3100 A. under small dispersion, with only a tentative analysis, have been obtained from 2000 A. to 5000 A. on sufficient dispersion for the vibrational analysis to be extended and for the rotational structure to be clearly resolved. Conditions for their emission are discussed and the probable process, involving dissociation followed by recombination, is outlined. On this basis the results obtained in discharges, ozonizers and high-voltage arcs are explained. Flory's suggestion of predissociation in the upper state is reviewed and the experimental evidence found to be against it. The conclusions reached are applied to considerations regarding the spectrum of the night sky.