Determination of N and O-atoms, of N2(A) and N2(X, v>13) metastable molecules and N+2 ion densities in the afterglows of N2-H2, Ar-N2-H2 and Ar-N2-O2 microwave discharges

Abstract

Early afterglows of N2-H2, Ar-N2-H2 and Ar-N2-O2 flowing microwave discharges are characterized by optical emission spectroscopy. The N and O atoms, the N2(A) and N2(X, v>13) metastable molecules and N+2 ion densities are determined by optical emission spectroscopy after calibration by NO titration for N and O-atoms and measurements of NO and N2 band intensities. In N2-(0.05-2.5 %)H2 and Ar-(1-50%)N2-(0.05-2.5%)H2 gas mixtures, the O-atoms are coming from O2 impurities in the discharge. Concentrations of these active species are compared to the ones obtained in Ar-(5-50%)N2-(0.2-2.5%)O2 gas mixtures in which a controlled amount of O2 is added.