Quantum analysis of the rotational structure of the first positive bands of nitrogen (N 2 )

Abstract

The greenish-yellow afterglow of active nitrogen was first described, by Lewis. Two decades have passed since Fowler and Strutt showed that this afterglow was due to a selective excitation of a few green, yellow and red bands belonging to the first positive system of the nitrogen molecule (N 2 ). Recent work on active nitrogen indicates that the selective excitation is due to metastable nitrogen atoms giving up their energy to metastable nitrogen molecules in state A, the final state of the first positive bands, thus leading to the selective excitation of certain specific vibrational levels in state B, the initial state of the first positive bands. The molecule then returns to state A, at the same time emitting the bands which constitute the afterglow. From the rotational analysis of the second positive nitrogen bands by Lindau, and Hulthèn and Johansson, it is known that state B corresponds to a 3 II state, the second positive bands having their final state in common with the initial state of the first positive bands. No definite information has been found concerning the electronic configuration of the nitrogen molecule which gives rise to state A. This can be obtained by making a detailed analysis of the rotational structure of the first positive nitrogen bands.