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Reactions of vibrationally excited OH

1977; Elsevier BV; Volume: 16; Issue: 1 Linguagem: Inglês

10.1016/s0082-0784(77)80376-7

1878-027X

John E. Spencer, Harumi Endo, G. Glass,

Spectroscopy and Laser Applications

Reactions of OH(ν=0, 1 and 2) with several species that play an important role in hydrocarbon combustion have been studied, at 295 K, in a fast discharge flow apparatus attached to an epr spectrometer. Rates of physical deactivation and of chemical reaction have been determined separately in the presence of sufficient argon to ensure rotational thermalization. Vibrationally excited OH was obtained from two sources: (1) the reaction O+HBr→OH(ν=1)+Br, which produces OH(ν=1) in 97% yield, and (2) the reaction H+NO2→OH(ν)+NO, which produces large amounts of OH in ν=2, 1 and 0. Rate constants for physical deactivation of OH(ν=1) by O, CO, H2 and CH4 were measured as (1.5±0.3)×10−10, <3×10−13, <10−14 and (3.4±0.5)×10−13 cm3 molecule−1 sec−1 respectively. For the reactions, OH(ν=1)+O→H+O2 (5) OH(ν=1)+CO→H+CO2 (19) OH(ν=1)+H2→H2O+H (21) OH(ν=1)+CH4arH2O+CH3, (22) the following rate constants were determined: k5=(9±3)×10−11, k19≤3×10−13, k21≤10−14 and k22≤3×10−14 cm3 molecule−1 sec−1. The rate constants for the overall removal of OH(ν=2) and OH(ν=1) by CO were estimated as (2.6±0.5)×10−13, and (3.3±0.5)×10−13 cm3 molecule−1 sec−1, respectively. OH(ν=2) was removed by H2 at a rate similar to that for OH(ν=1)