The mechanism and kinetics of the HCO + HONO → HCHO + NO2 reaction — A DFT study

The hydrogen-transfer reaction of HCO + HNO2 → HCHO + NO2 has been studied using both the density function theory (DFT) and high-level ab initio method. Three complete reaction paths have been located for the transfer reaction. Geometry optimization and frequency calculation have been performed at the B3LYP/6-311++G** level. QCISD(T) and G3B3 methods have been used to verify the single-point energy. On the basis of the ab initio data, the rate constants have been deduced over a temperature range of 300–3000 K using the transition-state theory and canonical variational transition-state theory with small-curvature tunneling effect. The calculated rate constants have been compared with the previous reported values.Key words: density function theory, reaction mechanism, variational transition-state theory, rate constant.