Recombination and Afterglow in Nitrogen and Oxygen

Abstract

Measurements were made on pure ${\mathrm{N}}_{2}$, using standard microwave cavity techniques, of the coefficient of electron recombination, $\ensuremath{\alpha}$. Pressures ranged from 3 to 30 mm Hg. Spectrograms were obtained of the afterglow. Higher vibrational levels of the second positive bands are enhanced relative to those obtained from electronic excitation. Goldstein-Kaplan bands, the green bands of Gaydon, and the Herman bands in the range 7000-9000 A were also relatively much stronger. The (0,0) first negative band was observed 1500 microseconds after the end of the discharge. Light intensity measurements by means of a photomultiplier tube showed a peculiar behavior of the relative intensities of the first positive and second positive bands. The number of photons emitted was large as compared to the number of electron-ion pairs recombining.In the afterglow of oxygen the only light observed was the (0,0) atmospheric band and weak radiation in the region 3500 A to 4500 A, which is thought to be a continuum. The continuum decreases in intensity as though it were the result of a two-body process.