Radiation of nitrogen molecules in a dielectric barrier discharge with small additives of chlorine and bromine

Abstract

Spectral and energy characteristics of nitrogen molecule radiation in dielectric barrier discharges in Ar-N2, Ar-N2-Cl2, and Ar-N2-Br2 mixtures were investigated experimentally. Small additives of molecular chlorine or bromine to an Ar-N2 mixture are found to increase the radiation intensity of the second positive system of nitrogen. The conditions at which the radiation spectrum predominantly consists of vibronic bands of this system are determined. Using a numerical model of plasmachemical processes, it is shown that, at electron temperatures typical of gas discharges (2–4 eV), a minor additive of molecular chlorine to an Ar-N2 mixture leads to an increase in the concentrations of electrons, positive ions, and metastable argon atoms. In turn, collisional energy transfer from metastable argon atoms to nitrogen molecules results in the excitation of the N2(C 3Π u ) state.