Spectra Emitted from Solid Nitrogen Condensed at 4.2°K from a Gas Discharge

Products of an electrical discharge in flowing nitrogen are frozen at liquid helium temperatures. The solid material emits a glow. Emission spectra have been obtained in the region 2200 A to 7000 A. The most intense features of these spectra, five sharp lines near 5230 A and three diffuse lines between 5530 A and 5670 A, are attributed to radiation from nitrogen atoms as affected by the solid lattice. There is a less intense series of bands, degraded to the red, extending from 3500 A to 6400 A. This system most probably arises from a transition of the ${\mathrm{N}}_2$ molecule, probably to the $A{{}_{}{}^3{}_{}{}^{}\Sigma _u^{}{}_{}{}^{}}^{+}$ state. In the same region there is a group of very weak diffuse bands which may be emission from N${\mathrm{O}}_2$. In addition several weak bands are attributed to the beta and gamma systems of NO and to NH.