Comment on Paper by D. C. Cartwright, S. Trajmar, and W. Williams, ‘Vibrational population of theA³Σu+andB³Πgstates of N2in normal auroras’

Summary. Recent theoretical calculations have given rise to the declared but unobserved presence of strong auroral emissions in the N2 A³Σu+-B³Πg and W³Δu-B³Πg systems. We suggest in the following discussion that the quantities involved are too uncertain for one to arrive at a well-defined conclusion on the basis of the theoretical calculations alone. Laboratory evidence at low pressures gives no direct indication of the presence of the systems, although this lack may be due to high radiationless deactivation rates of the W³Δu and A³Σu+ states. However, the presence of the transitions at the indicated rates should be easily detectable in the measured auroral population rates of the B³Πg state. According to averaged auroral measurements accumulated over the years, there is no evidence for significant contributions from the two systems in question.