Two-body dissociation of C3H4 isomers investigated by 50 keV/u Ne8+ impact.

The fragmentation of two isomers of C3H4, propyne (CH3CCH) and allene (CH2CCH2), is investigated by 50 keV/u Ne8+ impact. Obvious isomer effects are observed by comparing the time-of-flight spectra generated from the two isomers. Six two-body fragmentation channels of C3H4 2+ dications are identified for each isomer. CH2 + + C2H2 + is found to be the most favored CC bond breaking channel for both isomers, indicating that CH3CCH2+ intends to rearrange to the structure containing the CH2 group before fragmentation. For CH bond breaking channels, it is found that the CH3CCH which contains a CH3 group is more efficient for H2 + and H3 + ejection. In addition, two-body dissociation channels of C3H4 3+ trications are identified. While the H+ + C3H3 2+ channel is observed in the fragmentation of both isomers, the H2 + + C3H2 2+ channel only occurs in the fragmentation of CH3CCH3+. For CH2CCH2 3+, the peak and shoulder structures in the kinetic energy release spectrum of the H+ + C3H3 2+ channel are attributed to different geometries of the C3H3 2+ product.