Spectral analysis and kinetic modeling of radioluminescence in air and nitrogen

In this article we present a quantitative analysis of the second positive system of molecular nitrogen and the first negative system of the molecular nitrogen cation excited in the presence of ionizing radiation. Optical emission spectra of atmospheric air and nitrogen surrounding ²¹⁰Po sources were measured from 250 to 400 nm. Multi-Boltzmann and non-Boltzmann vibrational distribution spectral models were used to determine the vibrational temperature and vibrational distribution function of the emitting N₂(C³Π_u) and N₂⁺(B²Σ+u) states. A zero-dimensional kinetic model, based on the electron energy distribution function (EEDF) and steady-state excitation and de-excitation of N₂(X¹Σ+g), N₂⁺(B²Σ+u), N₂⁺(X²Σ+g), N₄⁺, O₂⁺, and N₂(C³Π_u, v), was developed for the prediction of the relative spectral intensity of both the N₂⁺(B²Σ+u → X²Σ+g) emission band and the vibrational bands of N₂(C³Π_u → B³Π_g) for comparison with the experimental data.