The dynamics of hydrogen/proton emission in three-body fragmentation of C 4 H 4 S 3 + induced by electron-impact

The three-body fragmentation dynamics of thiophene trications C 4 H 4 S 3 + induced by 200 eV electron-impact are investigated. All fragment ions are detected in coincidence, and their momentum vectors are determined by employing a reaction microscope. The detailed kinematical information of three-body fragmentation channels of H + C 3 H 2 2 + + C H S + , H + + C 3 H 2 + + C H S + , and H + + C 2 H 2 + + C 2 H S + is obtained. With detailed analysis of the KER-θ correlation maps, momentum correlation maps, Newton diagrams, and kinetic energy release (KER) spectra for each fragmentation channel, the results show that all three channels are primarily generated by sequential fragmentation processes. In the neutral H loss channel, hydrogen emission occurs in the first step of sequential fragmentation. For two deprotonation channels, each channel has two pathways, corresponding to proton emission in the first or second step of sequential fragmentation, respectively. These results reveal the mechanisms and dynamics of hydrogen/proton emission and ring-breaking reactions in the three-body fragmentation processes of heterocyclic molecules.