New theory of active nitrogen

Abstract

The details of the collisional quenching of N2 (B 3Π)ν′1 are crucial to theories of active nitrogen. It is concluded that quenching of N2(B 3Π)ν′1 occurs by transfer to lower energy ν′2 levels of the A 3Σu+ state but with large rotational energy and that collisional transfer of N2(A) to N2(B) also produces high rotational energy in N2(B). The observed quenching of N2(B 3Π)ν′1 corresponds to rapid rotational relaxation and electronic state interchange that appear as fast vibrational relaxation down a ladder formed of both A and B vibrational levels. Formation of N2(A 3Σ)ν′2 by atom association and relaxation down the A−B ladder contributes a pressure independent term (above 1 torr) to the intensity of the N2 1st positive bands (1+) as suggested by Thrush and Golde. An additional process that involves the 5Σ and W 3Δ state, largely populated from N2(A) via N2(B), contributes a pressure dependence to the 1+ bands under suitable circumstances and permits population of low ν′ levels of B 3Π even in the absence of collisional energy degradation.