Radiative transition probabilities of diatomic N2, O2, N2 + and NO in air plasmas

Abstract

Transition probabilities data (Frank–Condon factors, Einstein coefficients and absorption oscillator strengths) are the indispensable parameters for the calculations of radiative properties in thermodynamic equilibrium or nonequilibrium plasmas. Constructing an accurate transition probability database is of great significance not only for spectral simulations but also for spectroscopic diagnosis. Although there are already some published transition probabilities data, they are determined by using the relatively old electron transition moments and spectroscopic constants. With the rapid development of ab initio method, many newest data of electron transition moments and spectroscopic constants have been reported. Based upon these data, this study aims to rebuild a higher accuracy transition probabilities database for the main diatomic species in air plasmas produced by high-temperature Earth re-entry. The calculated results were systematically verified by the available numerical and experimental data of vibrational radiative lifetimes. Finally, the spectral absorption line intensities were studied using the constructed transition probabilities to show the importance of high rovibrational at high temperatures.