Yields of O 2 ( 1 Σ g + ) and O 2 ( 1 Δ g ) in the H + O 2 reaction system, and the quenching of O 2 ( 1 Σ g + ) by atomic hydrogen

The generation of metastable O 2 ( 1 Σ g + ) and O 2 ( 1 Δ g ) in the H + O 2 system of reactions was studied by the flow discharge chemiluminescence detection method. In addition to the O 2 ( 1 Σ g + ) and O 2 ( 1 Δ g ) emissions, strong OH( v = 2) → OH( v = 0), OH( v = 3) → OH( v = 1), HO 2 ( 2 A ′ 000 ) → HO 2 ( 2 A ″ 000 ), HO 2 ( 2 A ′ 001 ) → HO 2 ( 2 A ″ 000 ), and H O 2 ( 2 A ″ 200 ) → HO 2 ( 2 A ″ 000 ) emissions were detected in the H + O 2 system. The rate constants for the quenching of O 2 ( 1 Σ g + ) by H and H 2 were determined to be (5.1 ± 1.4) × 10 −13 and (7.1 ± 0.1) × 10 −13 cm 3 s −1 , respectively. An upper limit for the branching ratio to produce O 2 ( 1 Σ g + ) by the H + HO 2 reaction was calculated to be 2.1%. The contributions from other reactions producing singlet oxygen were investigated.