A vibrational analysis of the O2 ( A3Σ+u) Herzberg I system using rocket data

Abstract

An observation of the u.v. nightglow between 2670 and 3040 Å was conducted over White Sands Missile Range on 22 October 1984. A 1 4 m spectrometer operating at 3.5 Å resolution viewed the Earth's limb at tangent heights between 90 and 110 km for 120 s. A total of 41 spectral scans of the nightglow were obtained with the brightest feature being the O 2 ( A 3 Σ u +− X 3 Σ g −) Herzberg I bands. The data were sorted into two groups, one from the top side of the layer and one containing the emission peak, and compared with synthetic spectra. The deduced O 2 ( A 3 Σ u +) vibrational distributions indicate that at low altitudes, the higher vibrational levels ( v ́ > 6) were relatively depleted; however, the magnitude of the vibrational shift is much less than that predicted from theories of vibrational relaxation. It is shown that increasing the electronic quenching of O 2 ( A 3 Σ g +) with respect to the vibrational quenching can reduce the vibrational shift in the model and qualitatively explain the observations; however, several details of the vibrational distribution are not well reproduced.