Optical Study of Radicals (OH, O, H, N) in a Needle-plate Negative Pulsed Streamer Corona Discharge

Abstract

Optical emission spectroscopy has been applied to study the OH radicals and O, H, and N active atoms produced by a high-voltage negative pulsed streamer corona discharge of N2 and H2O mixture gas in a needle-plate reactor at one atmosphere. The relative vibrational populations and the vibrational temperature of N2(C, v′) were determined. The effects of pulsed peak voltage, pulsed repetition rate, and the addition of O2 on the relative populations of OH(A2Σ) radicals, O(3p5P), Hα (3P), and N(3p4P) active atoms were investigated. It was found that the relative populations of those radicals increase with increasing pulsed peak voltage and pulsed repetition rate. The relative population of OH(A2Σ) radicals decreases with increasing O2 flow rate, while the relative populations of O (3p5P), Hα (3P), and N (3p4P) active atoms exhibit a maximum over the studied range of the O2 flow rate. The involved physicochemical processes have also been discussed.