Optical Emission from a Pulsed Corona Discharge and Its Associated Reactions

Abstract

In order to investigate some chemical reactions occurring in the early stage of pulsed corona discharges intended for the conversion of nitrogen oxides, we studied the time dependence of optical emissions. Special attention has been paid to the decay time constants of populations of species excited by radical-molecule reactions. By systematically changing the partial gas pressure of minor gas components, we estimate the reaction rate contributions of these particular gas constituents. We conclude that NO(B²Π) is predominantly excited by the reaction of N(²D) with N₂O, while NO(A²Σ⁺) and OH(A²Σ⁺) are mainly excited by the energy transfer from N₂(A³Σ_u ⁺). The rotational temperature in the active discharge zone was estimated to be about 500 K from the second positive and first negative band emissions of nitrogen.