The unimol. charge-sepn. reactions of the doubly charged ions [C6H4Cl2]2+, [C6H3Cl]2+ produced in the ion source by electron impact from o-, m-, and p-dichlorobenzene were studied using mass analyzed ion kinetic energy spectrometry. The values of kinetic energy releases (T) can be calculated from the energy dispersion of product ions. As T essentially reflects the release of Coulomb energy, it can be used to calculate the approx. distances R between the 2 charges immediately before decomposition of the ions. From these data, some structural information about transition states could be provided. The electron-capture-induced decomposition (ECID) and collision-induced dissociation (CID) processes of these ions were also studied. The CID reactions of (C6H4Cl2)2+ could be used to distinguish the 3 dichlorobenzene isomers.

Key words: DICHLOROBENZENE, DOUBLE-CHARGE ION