Optical Spectroscopic Investigation of Ar/CH ₃ OH and Ar/N ₂ /CH ₃ OH Atmospheric Pressure Plasma Jets

Ar/CH ^₃ OH and Ar/N ₂ /CH ₃ OH plasma jets were generated at atmospheric pressure by dual-frequency excitations. Two different cases were studied with focus laid on the generation of CN radicals. In one case Ar gas passed through a bubbler with saturated methanol steam but without addition of N ₂ (Ar/CH ₃ OH plasma). In the other case N ₂ passed through the bubbler with saturated methanol steam (Ar/N ₂ /CH ₃ OH plasma). The optical emission lines of CN radicals have been observed in these two cases of plasma discharges. The addition of N ₂ can significantly increase the optical emission intensity of CN bands.