The reaction of H + CH2O: addition vs. abstraction

The reaction of H and CH2O, which plays an important role in combustion of hydrocarbons and alcohols, was studied in details using high-level coupled cluster calculations to construct a potential energy surface. This is followed by E,J-resolved master equation analyses to obtain rate constants as a function of both temperature and pressure. It is observed for the first time that the H-addition mechanism plays only a minor role (<10%), and can be neglected at high temperature in combustion environments. The direct H-abstraction pathway exclusively yields H-2 plus CHO. The calculated rate constants from the first principles agree reasonably well with experiments for a wide range of temperatures between 250 and 3500 K. When there are no experimental data, we provide highly accurate rate constants for kinetics modelling.