Fragmentation of C₂H₄²⁺ produced by 300 eV electron impact

The fragmentation of C₂H₄ ²⁺ produced by 300 eV electron impact has been investigated. Both 2-body and 3-body fragmentation channels were observed with an ion–ion coincidence technique. Using the recoil ion momentum spectroscopy, the momentum vector of each ionic fragment was measured and the kinetic energy release (KER) distributions for different fragmentation channels were obtained. For 2-body fragmentation channels, the branching ratios and the peak values of the KER distributions were compared with previous photon ionization experiments. The electronic state information of the parent ion C₂H₄ ²⁺ was inferred by comparing the present measured KER values and the predictions in previous works. For 3-body fragmentation channels, the dissociation mechanisms were analyzed according to the signature on the Newton diagram. (paper)