Emission Spectrum of N₂O+

Abstract

IN the course of a study of the luminescence of gases irradiated by X-rays (to be published), some unknown bands were observed from nitrous oxide. All the other gases studied emit well-known band systems, usually of the parent gas or its ion. Gases at pressures between 1 and 700 mm. were irradiated with soft X-rays (45 kV. peak) from a beryllium-window tube, and the spectra photographed or scanned with a photomultiplier through a Hilger D.96 f 2 quartz spectrograph. The emission from nitrous oxide consisted of the unknown bands at about 3680, 3540 and 3380 A. and the nitric oxide β system (the bands in the ν′ = 0 progression between ν″ = 3 and 13 were observed). The latter system has been observed previously as fluorescence from nitrous oxide irradiated with vacuum ultra-violet light¹. The two sets of bands differ in their dependence on pressure; the β bands suffer little collisional deactivation at high pressures whereas the new bands are strongly ‘quenched’, but they must be much more strongly excited since the intensities are roughly comparable at 600 mm. Since carbon dioxide excited by X-rays emits CO₂+ bands (²∑_u − ²Π_g, ref. 2, and ²Π_u − ²Π_g, ref. 3) and these show a similar pressure dependence, the new bands are tentatively ascribed to N₂O+. Emission by nitrous oxide (N₂O) itself is unlikely from a consideration of its excited states⁴.