Three-body fragmentation dynamics of CH2CCH23+ investigated by 50-keV/u Ne8+ impact

The three-body fragmentation dynamics of triply charged allene (${\mathrm{CH}}_{2}{\mathrm{CCH}}_{2}^{3+}$) induced by 50-keV/u ${\mathrm{Ne}}^{8+}$ ion impact is studied by measuring the charged fragments in coincidence using the reaction microscope. We focus on the fragmentation dynamics of two completely measured fragmentation channels, ${\mathrm{H}}^{+}+{\mathrm{CH}}^{+}+{\mathrm{C}}_{2}\mathrm{H}{{}_{2}}^{+}$ and ${\mathrm{H}}^{+}+\mathrm{CH}{{}_{2}}^{+}+{\mathrm{C}}_{2}{\mathrm{H}}^{+}$, for which breakage of one CH bond and one CC bond occurred during fragmentation. Both concerted and sequential dissociation mechanisms are observed for these two channels. For sequential process, we found that CH bond cleavage in the first step followed by CC cleavage is the major contribution for both channels. However, the process in which breakage of the CC bond is prior to CH breakage is observed for only the ${\mathrm{H}}^{+}+\mathrm{CH}{{}_{2}}^{+}+{\mathrm{C}}_{2}{\mathrm{H}}^{+}$ channel. The relative contributions of different fragmentation pathways are determined.