High-temperature photoionization cross-sections of O₂, N₂ and NO

Photoionization cross-sections for nitric oxide (NO), oxygen (O₂), and nitrogen (N₂) are critical for modeling various high-temperature, non-equilibrium gas environments. While extensive data exist for cold gases, high-temperature photoionization remains underexplored. This study presents a comprehensive model for the photoionization of NO, O₂, and N₂ in the vacuum ultraviolet (VUV) spectral range. The model incorporates both direct ionization and autoionization mechanisms, which have been calibrated against experimental data from cold environments and extrapolated to temperatures in the 300–10,000 K range. Tabulated results are provided for integration into physical simulations.