Ultraviolet Bands of CO in the Electrodeless Ring Discharge

The relative intensities of the band systems of CO in the region 2900 to 2150A obtained in an electrodeless ring discharge at various pressures were observed, and compared with Geissler tube spectra. A continuous wave oscillator using 100 watts at 6400 kilocycles was used to produce the ring discharge.Cameron bands. This system was well developed in the ring at low pressures, in contrast with results obtained by Herzberg who failed to obtain it in the ring excited by damped oscillations. The 0-1 band at 2157A was observed in addition to previously known members of the system.Bands of the CO⁺ ion. In the ring at all pressures, the first negative bands (CO⁺) were strong, indicating the presence of ions in the ring. The comet-tail bands, due to the same ion, appeared only at low pressures.Fourth positive bands. This system is very strong in the Geissler tube, and in the ring at high pressures. At low pressures it is very weak in comparison with the Cameron bands.The observations show that the electrodeless ring discharge affords a means of selective excitation of certain band systems, and should prove of value in the study of overlapping systems.