Two New Band Systems in the Near Ultraviolet Spectrum of N2

Two new weak band systems have been identified under high resolution in the near ultraviolet emission spectrum of molecular nitrogen. They are found to arise from a transition from a hitherto unknown 1Πg state, which it is proposed to call k, to the a′ 1Σu− and w1Δu states. The upper state is interpreted as the 1ΠgRydberg state of configuration … (1πu)4 (3σg) 3dπg. Straightforward treatment of the data by conventional methods gives B0d = 1.906 cm−1, B1d = 1.824 cm−1, T0 = 113 630.87 cm−1, and ΔG1/2 = 2305.92 cm−1. Only the d levels, i.e., the levels corresponding to the 1Πg− component, are observed and the absence of the c levels is attributed to an unusual type of predissociation involving the predicted stable 1Σg+ state which goes to the dissociation limit 2D + 2D (14.522 eV) and the 3Σg− state which arises at the limit 4S + 2P (13.332 eV). A new level at 117 661.11 cm−1 with a Bd value of 1.695 cm−1 is identified as v = 2 of the y1Πg state. A strong homogeneous interaction is found to be occurring between the new k1Πg state and the y1Πg state. A deperturbation calculation is carried out and yields the following deperturbed constants: k1Πg: Be = 1.959 cm−1; αe = 0.031 cm−1; re = 1.109 Å; T0 = 113 723.58 cm−1; ΔG1/2 = 2182.32 cm−1, y1Πg: Be = 1.739 cm−1; αe = 0.017 cm−1; re = 1.177 Å; Te = 114 314.36 cm−1; ωe = 1906.43 cm−1; αexe = 37.51 cm−1.