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 $\epsilon$-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 $X^{\prime }\Sigma$ state of ${\mathrm{N}}_2$ is very good, but there is no agreement between the upper state and the well-known metastable $A{}_{}{}^3{}_{}{}^{}\Sigma$ state. The upper state, or the initial state in emission, corresponds to a new level of ${\mathrm{N}}_2$, probably the ${}_{}{}^3{}_{}{}^{}\Sigma$ level which is produced from two ${}_{}{}^4{}_{}{}^{}S$ atoms. The bands of this system can be represented by the equation $\nu =49,766+(1460\mathrm{}{v}^{\prime }-21\mathrm{}{v}^{\prime 2})-(2345.16\mathrm{}{v}^{\prime \prime }-14.445\mathrm{}{v}^{\prime \prime 2}).\mathrm{}$ 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.