A possible pathway for the formation of the C2H3O+ chemi-ion

We have verified theoretically the assumption advanced by experimental groups that the CH3C radical in its ã4A2 excited state is one of the possible precursors of the CH3CO+ (X̃1A1) chemi-ion generated in the oxidation of 2-butyne. At the same time we have showed that the ground state of the CH3C radical cannot be such a precursor because of the existence of a potential barrier along the reaction coordinate in combination with its fast isomerization to CH2CH.