New Band System in Nitrogen

Abstract

The measurements of the new band system of nitrogen, which were first reported in a recent note have been revised. The members of this band system are identical with members of the $\ensuremath{\epsilon}$-system observed by Vegard in the luminescence of solid nitrogen. The revision was made possible by the successful photography of these bands on a spectrograph of larger dispersion than the one first used. The agreement between the lower state of these bands and the normal ${X}^{\ensuremath{'}}\ensuremath{\Sigma}$ state of ${\mathrm{N}}_{2}$ is very good, but there is no agreement between the upper state and the well-known metastable $A^{3}\ensuremath{\Sigma}$ state. The upper state, or the initial state in emission, corresponds to a new level of ${\mathrm{N}}_{2}$, probably the $^{3}\ensuremath{\Sigma}$ level which is produced from two $^{4}S$ atoms. The bands of this system can be represented by the equation $\ensuremath{\nu}=49,766+(1460{v}^{\ensuremath{'}}\ensuremath{-}21{v}^{\ensuremath{'}2})\ensuremath{-}(2345.16{v}^{\ensuremath{'}\ensuremath{'}}\ensuremath{-}14.445{v}^{\ensuremath{'}\ensuremath{'}2}).$ The excitation of these bands is ascribed to the presence of vibrating nitrogen molecules in the afterglow, and it is proposed that these bands may be used as a test for vibrating nitrogen molecules in the normal electronic state.