Gas phase recombination of OH with NO and NO2

摘要

The termolecular recombination of OH with NO and with NO2is studied for M=He, Ar, and N2at pressures from 1ndash;10 torr and temperatures from 230ndash;450deg;K in a flow tube using resonance fluorescence detection of OH radicals. The reactions are in their low pressure, third-order limit. The rate constants for the NO reaction at 295deg;K are 3.3, 3.4, and 5.8times;10minus;31cm6secminus;1in the above order of M gases. For the NO2reaction the corresponding values are 1.0, 1.0, and 2.3times;10minus;30, all with sgr;=plusmn;20 including estimates of systematic errors. Both recombinations show the expected negative temperature dependence, the Arrhenius activation energies being minus;1.7 kcal for NO and minus;1.8 kcal for NO2. These results are compared with all other published data and with RRKM unimolecular calculations.