Perturbations and rotational intensities observed in CN bands emitted by reactions of organic molecules with nitrogen atoms

Abstract

The rotational perturbations between the v = 0 level of the B 2Σ + electronic state and the v = 10 level of the A 2Π i electronic state of CN have been re-investigated. CN in the B 2Σ and A 2Π states was produced by the reaction of organic molecules with the nitrogen afterglow. Rotational analyses of the 10, 3 and 10, 5 bands of the A 2Π - X 2Σ system and of the 0, 0 band of the B 2Σ - X 2Σ system have been made. From the wavelength measurements the perturbed wave functions have been determined in terms of the unperturbed wave functions. The relative intensities of the perturbed lines, extra lines, and neighboring unperturbed lines have been studied as a function of pressure from 0.1 to 100 mm Hg. A new pair of extra lines has been found. At the higher pressures the populations of the excited rotational levels of CN approach a Boltzmann distribution. As the pressure is lowered the intensities of the perturbed and extra lines become continuously more anomalous. In the A- X bands no extra lines were found and the perturbed lines become weak, while in the B- X band the unperturbed lines are attenuated most and the extra lines are attenuated least. The interpretation is given that CN is formed in the A 2Π state more than 20 times as readily as it is formed in the B 2Σ state in reactions of organic molecules with the nitrogen afterglow.