Influence of electronically excited N2 and O2 on vibrational kinetics of these molecules in the lower thermosphere and mesosphere during auroral electron precipitation

The rate coefficients of vibrational excitation of ground-state molecules N2(X1Σg+) and O2(X3Σg−) in processes of the quenching of electronically excited molecules N2(A3Σu+, B3Πg, W3Δu, В′3Σu−, a′1Σu−, a1Πg, w1Δu) and O2(a1Δg, b1Σg+, c1Σu−, A′3Δu, A3Σu+) are calculated according to quantum-chemical approximations. Applying the calculated rate coefficients we have studied the role of inelastic intermolecular and intramolecular electron energy transfer processes in the production of vibrationally excited molecules at altitudes of the lower thermosphere and mesosphere during auroral electron precipitation. The study of vibrational populations (v′=2–30) of the X1Σg+ state of N2 at the altitudes of the lower thermosphere and mesosphere during auroral electron precipitation has shown three principal excitation mechanisms: radiational transitions from the A3Σu+ and a1Πg states for vibrational levels v′>10, intramolecular electron energy transfer process in N2(A3Σu+,v=0–5)+N2 collisions for vibrational levels v′=25–30 and the excitation by auroral electrons. Calculations have shown that transitions from two singlet a1Δg, b1Σg+, and three Herzberg c1Σu−, A′3Δu, A3Σu+ electronically excited states of molecular oxygen through radiational and collisional quenching are important in vibrational excitation of ground-state molecule O2(X3Σg−,v′=2–37).

► The production rate coefficients of vibrationally excited N2 and O2 are calculated.
► Quantum-chemical approximations are applied in the calculation.
► Vibrational kinetics of N2 and O2 at altitudes of lower thermosphere and mesosphere is studied.
► The influence of molecular collisions on the kinetics is investigated.