Absolute Rate Constants for the Reactions of HCO with O2 and NO from 298 to 503 K

Article abstract of DOI:10.1021/j150613a028

The absolute rate constants for the reactions HCO + O2 ---> HO2 + CO and HCO + NO ---> HNO + CO have been determined by using a flah photolysis-laser resonance absorption technique.The values obtained at 298 K are in units of cm³molecule^-1s^-1: k_O2=(5.6+/-0.6)E-12 and k_NO=(12.3+/-1.2)E-12.Negative temperature coefficients have been found between 298 and 503 K for both reactions: k_O2=5.5E-11 * T^-0.4+/-0.3 and k_NO=1.2E-10 * T^-0.4+/-0.3.Both formaldehyde and acetaldehyde were used as sources of formyl radicals.The total pressure was varied with no noticeable effect on the rate constants.Critical evaluation and recommendation are made in view of the previous results for use in atmospheric modeling.