Electronically excited molecular nitrogen and molecular oxygen in the high-latitude upper atmosphere

Abstract. Relative vibrational populations of triplet B³Π_g, W³Δ,sub>u, B^'3Σ_u⁻ states of N₂ and the b¹Σ_g⁺ state of O₂ are calculated for different altitudes of the high-latitude upper atmosphere during auroral electron precipitation. It is shown that collisional processes cause a wavelength shift in the distribution of relative intensities for 1PG Δv=3 sequence of N₂. The calculation of relative populations for vibrational levels v=1–5 of the b¹Σ_g⁺ state in the auroral ionosphere has not given an agreement with experimental results. Preliminary estimation of the contribution of the reaction O₂⁺+NO to the production of O₂(b¹Σ_g⁺) on the basis of a quantum-chemical approximation does not allow for an explanation of the observable vibrational population of the b¹Σ_g⁺ state in the aurora.