With Mass Analyzed Ion Kinetic Energy Spectrometry (MIKES), Collisional Induced Dissociation (CID), and Electron Capture Induced Decomposition (ECID) techniques, the doubly charged ions and singly charged ions from o-, m-, and p-diol benzene in the EI source have been studied. In terms of the values of the kinetic energy releases (T) of the charge separation reactions of the doubly charged ions and the estimated intercharge distances (R) of the exploding doubly charged ions the transition structures were proposed. Some structural information about the transition states was also obtained. It is of interest that the MIKES/CID spectra of singly charged ions [C6H6O2]^+ from the three isomers are of significant differences.

Key words: ISOMER, BENZENEDIOL