Kinetics of the O + O3 Reaction

The gas phase reaction $\mathrm{O}+{\mathrm{O}}_3\text{→ 2}{\mathrm{O}}_2$ was studied directly in a flow system under conditions of excess ozone, with O atoms produced by thermal decomposition of ${\mathrm{Ar–O}}_3$ mixtures on a Nernst glower, and measurement of the spatial O atom decay by $\mathrm{O}+\mathrm{NO}$ chemiluminescence with small, variable NO additions. The rate constant was found to be ${\text{(7.5 ± 0.6) × 10}}^{\text{−15}}\hspace{0.17em}{\mathrm{cm}}^3\hspace{0.17em}{\mathrm{molecule}}^{\text{−1}}·{\sec }^{\text{−1}}\hspace{0.17em}\mathrm{at}{\text{\hspace{0.17em}298}}^{\mathrm{o}}\mathrm{K}$ . Over the temperature range 269 to 409°K a rate expression ${\text{(1.05 ± 0.18) × 10}}^{\text{−11}}\hspace{0.17em}\exp \text{[(−4.31 ± 0.10\hspace{0.17em}}{\mathrm{kcal\; mole}}^{\text{−1}}\mathrm{)/RT]}$ is reported. The effects of interference by O₂(¹Δ_g) and product excitation are discussed, and the present results are compared with earlier investigations.