Ions detected for the three repeated experiments of irradiation of a N₂-CH₄ 95–5% gas mixture with photons at 73.6 nm and a reactant partial pressure of 32 Pa. The three experiments are reported with three distinct colors and the mass spectra are slightly shifted for clarity. Uncertainties are reported on each ion for each experiment, corresponding to twice the standard deviation of the ion signal variability, obtained by measuring a few tens of spectra for each experiment.