Three new isomers of [C 2 H 6 O] + ˙: The radical cations [CH 3 O(H)CH 2 ] + ˙, [CH 3 CHOH 2 ] + ˙ and a low‐energy isomer of unassigned structure

Three new [C 2 H 6 O] + ˙ ions have been generated in the gas phase by appropriate dissociative ionizations and characterized by means of their metastable and collisionally induced fragmentations. The heats of formation, Δ H f 0 , of the two ions which were assigned the structures [CH 3 O(H)CH 2 ] + ˙ and [CH 3 CHOH 2 ] + ˙ could not be measured. The third isomer, to which the structure \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 2} = \mathop {\rm C}\limits^{\rm .} {\rm H} \cdot \cdot \cdot \mathop {\rm H}\limits^ + \cdot \cdot \cdot {\rm OH}_{\rm 2} $\end{document} is tentatively assigned, was measured to have Δ H f 0 = 732±5 kJ mol −1 , making it the [C 2 H 6 O] + ˙ isomer of lowest experimental heat of formation. It was found that the exothermic ion–radical recombinations [CH 2 OH] + +CH 3 ˙→[CH 3 O(H)CH 2 ] + ˙ and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \mathop {\rm C}\limits^{\rm + } {\rm HOH + H}^{\rm .} $\end{document} →[CH 3 CHOH 2 ] + ˙ have large energy barriers, 1.4 and ⩾0.9 eV, respectively, whereas the recombinations yielding [CH 3 CH 2 OH] + ˙ have little or none.