A. Ricard, A. M. Diamy & J. C. Legrand. Density of \(N_2\) Active Species in \(N_2\) –x\(CH_4\) Afterglows With X= (0-7.5)10-4 by Mass Spectrometry and Optical Spectroscopy at Low Gas Pressure. PAWNST-E3 2023, 91-107.