Theoretical study on the kinetics and mechanism for the reaction of FCO with NO

The radical reaction mechanism of FCO + NO on the ground electronic state energy surface has been studied at the G2M level of theory based on the geometric parameters optimized at the B3LYP/6-311+G(d) level of theory. The two kinds of reaction pathways include the direct fluorine abstraction channel producing CO + FNO and the association channel forming the FC(O)NO complex. The former has a distinct barrier of 8.9 kcal mol(-1), while the latter is a barrierless association process. The rate constant of this reaction system in the temperature range 200-3000 K has been calculated by the microcanonical VTST/RRKM theory. The theoretical result shows that the predicted total rate constants exhibit a negative-temperature dependence and positive-pressure effect at lower temperatures. Under the experimental conditions, the predicted values are in good agreement with the experimental results. In addition, the predicted branching ratios clearly indicate that the dominant product channel is the formation of FC(O)NO at low temperatures and FNO + CO at high temperatures (>500 K).