THE PRESENCE OF EXCITED MOLECULES IN ACTIVE NITROGEN

Spectra of active nitrogen have been photographed under conditions comparable to those used for most studies of reactions of active nitrogen with other molecules. Bands observed were identified as the first positive system of nitrogen and the β- and γ-bands of nitric oxide. No trace of Vegard–Kaplan emission was observed. The 2 537 line of mercury was detected under certain conditions.The results are used to rationalize the large discrepancy which exists between estimates of the lifetime of N2(A3Σu+) by optical spectroscopy and reaction kinetics. In the former method, the measurements are performed in an oxygen-free system and are clearly related to a radiative lifetime. In the latter method, the measurements are performed in the presence of traces of oxygen and are believed to indicate a collisional lifetime. The reaction kinetic measurements are shown to be in complete agreement, both with regard to decay kinetics and lifetime, with electron spin resonance measurements on active nitrogen produced under near-identical conditions.