Effects of adding hydrogen to an argon glow discharge: overview of relevant processes and some qualitative explanations

An overview is given of the various processes which may occur in an argon-hydrogen glow discharge plasma, including the cross sections and rate coefficients compiled from the literature. Based on a simple balance equation, the dissociation degree of H-2 is estimated for typical GD-MS and GD-OES conditions. Further, the effects of H-2 molecules and H atoms on the argon analytical glow discharge are predicted, i.e., a drop in argon ion (and maybe electron) density, a drop in argon metastable atom density and a change in the electron energy distribution function. Based on these predicted effects, we try to explain observed changes in analytical characteristics.