The potential energy surface for the [C2H2O]+˙ system: The ketene radical cation [CH2CO]+˙ and its isomers

Ab initio molecular orbital calculations with large, polarization basis sets and incorporating valence electron correlation have been employed to examine the [C2H2O]+˙ potential energy surface. Four [C2H2O]+˙ isomers have been identified as potentially stable, observable ions. These are the experimentally well‐known ketene radical cation, [CH2CO]+˙ (a), and the presently unknown ethynol radical cation, [CH2COH]+˙ (b), the oxirene radical cation magnified image (c) and an ion resembling a complex of CO with [CH2]+˙, magnified image (d). The calculated energies of b, c and d relative to a are 189, 257 and 259 kJ mol−1, respectively. Dissociation of ions a and d is found to occur without reverse activation energy.