Theoretical study of activation Fe-O bond of FeO+ by CO in the gas phase

The entire reaction mechanism for the gas phase CO-CO2 conversion by FeO+ is discussed by means of the density functional theory and the intrinsic reaction coordinate approach. The calculated results have strongly indicated that the reaction of CO(1Σ+)+FeO+(4Δ/X6Σ+)→CO2(1Σg+)+Fe+(4F/X6D) is a spin-forbidden reaction between the quartet and the sextet potential energy surfaces (PESs). There is a crossing point between the quartet and the sextet potential energy surfaces which may play a significant role in this reaction, by which the activation energy can be decreased from −15.1 to −56.4 kJ mol−1 at the reaction system.