High-resolution Fourier spectrometry of 14N 2 infrared emission spectrum: Extensive analysis of the B3Π g- A3Σ u+ system

The B³Π _g- A³Σ _u⁺ system of N ₂ excited in a microwave discharge was recorded between 3 000 and 18 000 cm ^-1 with a high-resolution Fourier spectrometer. There are no observed irregularities in the levels of the A³Σ _u⁺ and B³Π _g states at least for the values of v and J considered here, except the predissociation in the B³Π _g state for v = 12 and J higher than 33. This predissociation will be checked with more complete data in another article. Thirty three bands of the first positive system with 0 ≤ v' ≤ 12 and 0 ≤ v″ ≤ 8 are analyzed. The molecular parameters of the B³Π _g and A³Σ _u⁺ are obtained by a complete fitting procedure. Derived values of equilibrium constants are deduced; RKR potential energy curves for the two states are constructed, and the Franck-Condon factors calculated for the A- B system.