Ultraviolet Spectra of the Nitrogen Pink Afterglow

Abstract

Ultraviolet spectra from 4200 to 1150 Å of the recurrent, brilliant afterglow in fast‐flowing pure nitrogen are obtained using a vacuum spectrometer at 0.5‐Å resolution with photographic and photoelectric detection. Molecular emission features generally resemble those of a direct discharge. Atomic lines from the 10.7‐eV 3s ²P level are present, but there are none from the 10.4‐eV 3s ⁴P level. Electrical quenching by a 60‐kc/sec field reduces the N₂⁺ bands more sharply than the N₂ bands or the N lines. Optical absorption and other measurements show that the concentrations of ground‐state and low‐lying metastable atoms are little affected by this afterglow or by its quenching.