Radiative recombination of Ar₂⁺ and enhanced dissociation of O₂ in a glow discharge

We have recently reported a significant enhancement in the atomization of O₂ in an Ar-O₂ glow discharge. During our investigations of energy transfer between Ar and O₂, we have observed a strong continuum emission from Ar₂⁺ in the 350-600 nm spectral region in a pure Ar discharge. We believe that capture of a free electron by the Ar₂⁺ ion leading to the formation of excited dimer Ar₂^* is responsible for this continuum. The dimer subsequently dissociates into Ar atoms. We further observe that in the presence of small amount of O₂, resonant charge-exchanging collisions yield O₂⁺ that subsequently capture free electrons and dissociate yielding up to a 30-fold increase in atomic O compared with the O-atom yield in pure O₂ discharge. In addition, the Ar line at 763.5 nm appears to be fed by the dissociating Ar₂^*.