Investigation of the mechanism of formation of chlorine atoms in chlorine-hydrogen plasmas

To explain the trend of an experimental dependence for concentration of chl orine atoms in a discharge, the principal processes of the formation and de cay in the plasma of a chlorine mixture with hydrogen were considered. The rate coefficients and rates of processes involving electrons were calculate d by mathematical modeling in order to reveal the contribution of each proc ess to the observed concentration of chlorine atoms. The greatest contribut ion is made by direct electron-impact dissociation. The experimental concen tration of chlorine atoms at a high percentage of hydrogen is explained by an increase in electron concentration and, hence, in the rate of the direct dissociation process. It is suggested that chain reactions can make a subs tantial contribution to the formation of atoms at low hydrogen concentratio ns.