New Band System in Nitrogen

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 ε-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^'Σ state of N₂ is very good, but there is no agreement between the upper state and the well-known metastable A³Σ state. The upper state, or the initial state in emission, corresponds to a new level of N₂, probably the ³Σ level which is produced from two ⁴S atoms. The bands of this system can be represented by the equation ν=49,766+(1460v^'-21v^'2)-(2345.16v^''-14.445v^''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.