HIGH-TEMPERATURE PHOTOCHEMISTRY KINETICS STUDY OF THE REACTION H + NO2-]OH + NO FROM 296-K TO 760-K

Rate coefficients for the H + NO2 --> OH + NO reaction have been measured by using the high-temperature photochemistry (HTP) technique. H atoms are generated by flash photlysis of CH4, and their relative concentration is monitored by time-resolved resonance-fluorescence detection. The data are well-fitted by the empirical expression k(T) = 2.2 x 10(-10) exp(-182 K/T) cm3 molecule-1 s-1 for the 296-760 K temperature range. The precision of the data is 7%, and the accuracy is estimated to be 21%, where both figures represent 2-sigma statistical confidence intervals. Comparison of the ratio of the experimental reaction cross sections, at the temperature extremes, to the theoretical ratio supports a zero energy barrier. The potential stabilization channel leading to HONO is discussed.