Shock tube study of the thermal decomposition of O3 from 1000 to 3000°K

Measurements have been made of the thermal decomposition of O3 behind incident shock waves. Both uv absorption and Schumann−Runge emission measurements were made in separate experiments to follow the O3 and O−atom concentrations, respectively. The high temperature data are interpreted to indicate a departure from the Arrhenius form for the rate constant of the unimolecular reaction O3 + M ? O + O2 + M. The rate constant for this reaction is measured to be approximately a factor of 2 smaller at 3000°K than predicted by the Arrhenius fit to the low temperature data (200°K ? T ⩽ 900°K).