Is the CH2OH + O2 → CH2 = O + HO2 Reaction Barrierless? An Ab Initio Study on the Reaction Mechanism

The reaction mechanism of the CH₂OH + O₂ gas-phase reaction was investigated by means of ab initio calculations. MP2 and QCISD methodologies were used to obtain the stationary points on the potential energy surface. Single-point high-level QCISD(T) calculations were performed over the QCISD results in order to refine the energy of the transition states and the minima found. A new transition state concerning the initial O₂ addition to the CH₂OH radical was found, not reported so far for this reaction. Extra CCSD optimisation and single-point high-level CCSD(T) calculations upon the QCISD results confirm this TS. Additional RASSCF calculations show that its wave function has no significant multireferential character.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.