Determination of N and O-Atoms, of N₂(A) and N₂(X, v > 13) Metastable Molecules and N₂<sup style="margin-left:-6px;">+</sup> Ion Densities in the Afterglows of Ar-N₂ Microwave Discharges

Abstract

Early afterglows of Ar-N 2 flowing microwave discharges are characterized by optical emission spectroscopy. The N and O atoms, the N 2 (A) and N 2 (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 N 2 band intensities. For an Ar-xN 2 gas mixture with × increasing from 2 to 100% at 4 Torr, 100 Watt and an afterglow time of 3 × 10 - 3 s at the 5 liter reactor inlet, it is found densities in the ranges of (2 - 6) × 10 14 cm - 3 for N-atoms, one order of magnitude lower for N 2 (X, v > 13) and for O-atoms (coming from air impurity), of 10 10 - 10 11 cm - 3 for N 2 (A) and of 10 8 - 10 9 cm - 3 for N 2 + .