Analysis of the Mid-Infrared Spectrum of the Exhaust Gas From an Atmospheric Pressure Plasma Jet (APPJ) Working With an Argon–Air Mixture

The mid-infrared (IR) absorption spectrum of the exhaust gas of an atmospheric pressure plasma jet operated in Ar with the admixture of 0.1% of air has been monitored in the spectral region from 4000 to 750 cm^-1. The absorption features of CO₂, CO, NO, NO₂, N₂O, HNO₂, and HNO₃ were identified using a Fourier transform IR spectrometer combined with a multipass cell with 30-m absorption path length. The production rates of these molecules to be in the range of 0.5 to 4 times10¹⁸ molecules s^-1 were estimated.