Generation of O2/1Delta/ by nuclear pumping

The mechanisms at work in the generation of O2(1Delta) in a nuclear-pumped plasma consisting of O2 plus a buffer gas, such as Ar, are investigated. It is noted that in this radiation-induced plasma, the rare-gas metastables that are formed transfer their energy to the oxygen. A kinetics model comprising 18 species and more than 150 reactions is described and is shown to give reasonable agreement with the measurements of O2(1Delta) to date. The dominant gas-kinetic reactions in the model are the dissociation of O2 into metastable O by Ar metastables, followed by O metastables reacting with O2 to produce O2(1Sigma) and superelastic collisions between 02(1Sigma) and electrons to produce O2(1Delta). What is more, three-body atomic oxygen recombination and direct excitation of O2 by electrons into O2(1Delta) are important production mechanisms. Both the modeling and experimental results suggest that sufficient O2(1Delta) is produced by nuclear pumping to make an O2(1Delta)-I2 transfer laser.