Bimolecular and ‘‘three-body’’ quenching of paschen-1s argon atoms by N2, H2, and O2 and effects of N2 on the yield of the first triplet argon excimer

Abstract

Rate constants for bimolecular quenching of Ar (1s) resonance-state and metastable atoms by N2, H2, and O2 have been measured by fast absoprtion spectrophotometry at argon pressures in the 102–103 Torr region at 298 K. ’’Three-body’’ quenching attributed to collisional relaxation of vibrationally excited dissociative excimer molecules by molecular quenching agents has been observed to occur efficiently for all Ar (1s) atoms in the presence of H2 and O2, but only for the resonance-state Ar (1s) species in the presence of N2. A discussion and analysis of the temporal behavior and the yield of Ar2 (3S+u) molecules in the context of the mechanism for Ar (1s) atom decay and excimer formation indicates that the predominant precursors of the first triplet argon excimer in Ar/N2 mixtures are probably Ar (3P2) atoms and Ar2 van der Waals molecules, the latter through the agency of N2 (C 3Ru) at higher N2 concentrations.