Laser magnetic resonance, resonance fluorescence, and resonance absorption studies of the reaction kinetics of O + OH → H + O₂, O + HO₂ → OH + O₂, N + OH → H + NO, and N + HO₂ → products at 300 K between 1 and 5 torr

A new tandem axis, laser magnetic resonance-resonance fluorescence-resonance absorption, fast flow system is used to examine the kinetics of four reactions in the oxygen-nitrogen-hydrogen free radical system. The experimental approach emphasizes simultaneous detection of reactants and products, cross calibration of detection axes, multiple sources for free-radical-formation steps, and computer simulation of the time dependence of reactants and products through the course of each reaction. Rate constants are reported as follows: OH + O → H + O₂, (3.1 ± 0.5) × 10^-11 cm³ molecule^-1 s^-1; HO₂ + O → OH + O₂, (5.2 ± 0.8) × 10^-11 cm³ molecule^-1 s^-1; OH + N → H + NO, (4.2 ± 0.8) × 10^-11 cm³ molecule^-1 s^-1; HO₂ + N → products, (2.2 ± 0.5) × 10^-11 cm³ molecule^-1 s^-1. Cited uncertainties are 95% confidence limits and include consideration of possible systematic errors. All experiments were done in helium or argon at 300 K and pressures between 1 and 5 torr.