Determination of N and O-atoms and N_2 (A) Metastable Molecule Densities in the Afterglows of N_2-H_2, Ar-N_2-H_2 and Ar-N_2-O_2 Microwave Discharges

摘要

Early afterglows of N_2-H_2, Ar-N_2-H_2 and Ar-N_2-O_2 flowing microwave discharges are characterized by optical emission spectroscopy. The N and O atoms and the N2(A) metastable molecule densities are determined by optical emission spectroscopy after calibration by NO titration for N and O-atoms and measurements of NO and N_2 band intensities. If an uncertainty of 30% is estimated on N-atomic density, an inaccuracy of one order of magnitude is obtained on the O and N_2 (A) densities. In N2-(0.05-2.5%)H_2 and Ar-(1-50%)N_2-(0.05-2.5%) H_2 gas mixtures, the O-atoms are coming from O_2 impurities in the discharge. Concentrations of N and O-atoms and of N_2 (A) densities are compared to the ones obtained in Ar-(5-50%)N2-(0.2-2.5%) O_2 gas mixtures in which a controlled amount of O_2 is added.