Comparison of [C6H6]2+ ion structures: Application of electron capture induced decomposition to the study of isomers

Structures of [C₆H₆]²⁺ ions formed by electron impact from benzene, 2,4-hexadiyne and 1,5-hexadiyne have been investigated by the recently developed electron capture induced decomposition method, by charge-separation reactions and by ion abundances in electron impact mass spectra. Significant differences were found among the isomers indicating the structural integrity of these [C₆H₆]²⁺ ions. The observed differences indicate that the most likely atomic configuration of [C₆H₆]²⁺ ions produced from benzene and 2,4-hexadiyne is the same as in the corresponding neutral species. A new method is suggested by which the structure (atomic configuration) of doubly charged ions may be determined.