Three new isomers of [C2H6O]+˙: The radical cations [CH3O(H)CH2]+˙, [CH3CHOH2]+˙ and a low‐energy isomer of unassigned structure

Abstract

AbstractThree new [C2H6O]+˙ 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, ΔHf0, of the two ions which were assigned the structures [CH3O(H)CH2]+˙ and [CH3CHOH2]+˙ 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} $\end{document} is tentatively assigned, was measured to have ΔHf0 = 732±5 kJ mol−1, making it the [C2H6O]+˙ isomer of lowest experimental heat of formation. It was found that the exothermic ion–radical recombinations [CH2OH]++CH3˙→[CH3O(H)CH2]+˙ and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \mathop {\rm C}\limits^{\rm + } {\rm HOH + H}^{\rm .} $\end{document}→[CH3CHOH2]+˙ have large energy barriers, 1.4 and ⩾0.9 eV, respectively, whereas the recombinations yielding [CH3CH2OH]+˙ have little or none.