Temperature dependence of the laser enhanced reaction NO+O3(001) →NO2(2B1,2)+O2

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Abstract
The ratio of the rate coefficient of the vibrationally enhanced reaction NO+O3→NO2*+O2 to the thermal rate coefficient was determined over the temperature range 155–303 K. This was accomplished by using a pulsed CO2 laser to excite the ozone molecules in a flow system. The enhancement of the rate coefficient was determined from the ratio of the laser‐induced chemiluminescent signal to the thermal dc signal and from the fraction of vibrationally excited O3 molecules in the gas mixture. The latter quantity was determined from measurements of laser beam attenuation in static gas mixtures, using the same cell and laser configuration. It was found that the activation energy was reduced by 1.29+0.25−0.22 kcal/mole or by 42±8% of the O3(001) vibrational energy, while the pre‐exponential factor was barely affected. The information theory of Levine and Bernstein predicts a much smaller reduction in the activation energy. On the other hand, the excitation function of Menzinger et al. indicates that an equivalent amount of translational (or rotational) energy would be 100% effective in reducing the observed activation energy.