Three-body fragmentation dynamics of C3H4 induced by 50-keV/u Ne8+ ion impact

The experiment on collision between 50-keV/u Ne8+ ion and C3H4 molecule is carried out by reactionmicroscopic imaging spectrometer. The process of forming the divalent ion from propylene (CH2CCH2)and proacetylene (CH3CCH) and then dissociating to produce H+ and C3H2+ ions and H atom is studied.Using the reaction microscope, the momentum vector of H+ ion and the momentum vector of ion aredirectly obtained, and then the momentum of the undetected fragment is reconstructed according to momentumconservation. By analyzing the kinetic energy of the three fragments and the total kinetic energy released fromthe dissociation process, the events with H atom as the third fragment are discriminated from H+, and thus theH+ ion, ion, and H atom are identified. In addition, it is found that the sequential fragmentation pathwayin which H+ ion and ion are produced in the first step followed by dissociation of into ionand H atom in the second step is the dominant dissociation mechanism according to the detailed analyses of the Dalitz plot, Newton diagram and a distribution