Nonequilibrium population of the first vibrational level of O2(1Σ) molecules in O2 — O2(1Δ) — H2O gas flow at the output of chemical singlet-oxygen generator

The concentrations of electron-excited particles have been determined by measuring the absolute spectral irradiance in the range of 600 — 800 nm of O₂ — O₂(¹Δ) — H₂O gas mixture at the output of a chemical singlet-oxygen generator (SOG). A nonequilibrium population of the first vibrational level of O₂(¹Σ) molecules has been clearly observed and found to depend on the water vapour content. In correspondence with the results of these measurements and according to the analysis of kinetics processes in the O₂ — O₂(¹Δ) — H₂O mixture, the maximum number of vibrational quanta generated in the O₂(¹Δ) + O₂(¹Δ) → O₂(¹Σ) + O₂(³Σ) reaction is 0.05 ± 0.03. It is concluded that the vibrational population of O₂(¹Δ) at the output of the SOG used in a chemical oxygen—iodine laser is close to thermal equilibrium value.