Quantitative spectroscopy of the aurora. V. The spectrum of strong aurora between 10 000 and 16 000 Å

Abstract

The auroral spectrum between 10 000 and 16 000 Å has been examined with a resolution of 12 Å by means of a Michelson interferometer. As a result of the high accuracy of the spectral data obtained by this technique, it has been possible to derive a pure auroral spectrum by subtracting the nightglow spectrum obtained under identical conditions in the absence of aurora. The spectrum was then matched by a synthetic spectrum composing N2 and N2+ bands and atomic lines so as to measure the intensities of the components of the auroral spectrum. The first positive N2 band intensities agree well with the values predicted from analysis of the spectrum below 11 000 Å. On the other hand the intensities of the Δν = −1 bands of the N2+ Meinel system make possible an improved electronic transition moment function, [Formula: see text], for the system. The vibrational population rates derived from the spectrum by means of the new function are closer than before to values predicted by the Franck–Condon principle.