Production of Oxygen Atoms in Quartz and Polytetrafluoroethylene Discharge Tubes

Abstract

THE dissociation of oxygen in a glow discharge depends markedly on the presence of additives, in particular molecules containing hydrogen and nitrogen1–3. Brown3, for example, found that the conversion to oxygen atoms in a microwave discharge at a pressure of 0.52 torr increases from 0.015 for very pure oxygen to 0.23 when 2 per cent water vapour is added. Kaufman4 has attributed this effect to a reduction in the surface activity for recombination. There is, however, a lack of quantitative data on how both additives and the surface of the discharge tube and tube immediately downstream from the discharge affect the conversion to oxygen atoms. Their effect on the yield of oxygen atoms, expressed by g atoms produced/kWh of energy absorbed by the gas, is also poorly known. We present here some results of conversion to oxygen atoms and yields obtained when dry and moist oxygen were decomposed by microwave energy in poly-tetrafluoroethylene (PTFE), uncoated quartz and quartz tubes coated with syrupy orthophosphoric acid.