Measuring the Density of N\(_2\) Active Species in N\(_2\) –xCH\(_4\) Afterglows with x= (0-7.5)10\(^{-4}\) by Mass Spectrometry and Optical Spectroscopy at Low Gas Pressure

Abstract

The density of N-atoms in N₂ pink and late microwave flowing afterglows has been investigated by mass spectrometry and NO titration. By optical spectroscopy, it has been obtained after NO titration the density of N₂(B,11), N₂(C,0) and N₂⁺(B,0)) radiative states and of N₂(A), N₂⁺ metastable and ionic molecules. By introducing a few CH₄ into N₂, the density of C-atoms added to N-atoms is measured in the pink afterglow. The N₂ pink afterglow was observed when the N₂(B,v’=16-18) levels appeared after the autodissociative N₂(B,v’=13-15) states, contrary to the late afterglow where the N₂(B,v’=16-18) levels could not be detected.