Collision Processes in a CO2 Laser Plasma

Abstract

The neutral and ionic population of a plasma in a CO2 laser gas mixture was analyzed mass spectrometrically. Comparative measurements of the CO2 concentration at the cathode and anode side of the discharge show that the strongest regeneration of CO2 is at the cathode side. The oxidation mechanisms of CO (regeneration of CO2) in the He–N2–CO2 plasma is consistent with O(1D)+CO→CO2or alternatively O(1D)+CO2→CO3,CO3+CO→2CO2.If water vapor is added to the triple mixture, the CO2 is more effectively regenerated and the reaction OH+CO→CO2+H plays probably an important role. The molecule CO3 has been previously postulated, but has never been observed. In the mass spectra of the gas mixture with water vapor, mass 60 is observed and is assumed to be CO3.