New mechanism of O 2(a 1 Δ g) quenching in oxygen contained plasmas

Singlet oxygen excitation in RF discharge at 13.56 MHz was studied experimentally and theoretically in the pressure range of 2 - 20 Torr. It was shown, that the saturation of O2(a1Δg) concentrations with input power at high oxygen pressures is due to quenching of O2(a1Δg) by atomic oxygen in three-body process. Removing of atomic oxygen using HgO coatings on the tube wall allows to remove saturation and to increase in three times the O2(a1Δg) concentrations at 15 Torr. The record values of singlet oxygen (SO) yield of about 10% are obtained for the first time in gas discharges at high oxygen pressures of 10 - 20 Torr.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.