Three-body fragmentation dynamics of C<sub>3</sub>H<sub>4</sub> induced by 50-keV/u Ne<sup>8+</sup> ion impact
Authors: Li Tao-Tao , Yuan Hang , Wang Xing , Zhang Zhen , Guo Da-Long , Zhu Xiao-Long , Yan Shun-Cheng , Zhao Dong-Mei , Zhang Shao-Feng , Xu Shen-Yue , Ma Xin-Wen ,   MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China,   Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: February 2022

The experiment on collision between 50-keV/u Ne<sup>8+</sup> ion and C<sub>3</sub>H<sub>4</sub> molecule is carried out by reaction microscopic imaging spectrometer. The process of forming the <inline-formula><tex-math id="Z-20220503101319-1">\begin{document}$\rm C_3H_4^{2+}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101319-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101319-1.png"/></alternatives></inline-formula> divalent ion from propylene (CH<sub>2</sub>CCH<sub>2</sub>) and proacetylene (CH<sub>3</sub>CCH) and then dissociating to produce H<sup>+</sup> and C<sub>3</sub>H<sup>2+</sup> <inline-formula><tex-math id="Z-20220503101357-1">\begin{document}$\rm C_3H_2^+$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101357-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101357-1.png"/></alternatives></inline-formula> ions and H atom is studied. Using the reaction microscope, the momentum vector of H<sup>+</sup> ion and the momentum vector of <inline-formula><tex-math id="Z-20220503101436-1">\begin{document}$\rm C_3H_2^+$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101436-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101436-1.png"/></alternatives></inline-formula> ion are directly obtained, and then the momentum of the undetected fragment is reconstructed according to momentum conservation. By analyzing the kinetic energy of the three fragments and the total kinetic energy released from the dissociation process, the events with H atom as the third fragment are discriminated from H<sup>+</sup>, and thus the H<sup>+</sup> ion, <inline-formula><tex-math id="Z-20220503101513-1">\begin{document}$ \rm C_3H_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101513-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101513-1.png"/></alternatives></inline-formula> ion, and H atom are identified. In addition, it is found that the sequential fragmentation pathway in which H<sup>+</sup> ion and <inline-formula><tex-math id="Z-20220503101547-1">\begin{document}$\rm C_3H_3^+$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101547-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101547-1.png"/></alternatives></inline-formula> ion are produced in the first step followed by dissociation of <inline-formula><tex-math id="Z-20220503101620-1">\begin{document}$ \rm C_3H_3^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101620-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101620-1.png"/></alternatives></inline-formula> into <inline-formula><tex-math id="Z-20220503101656-1">\begin{document}$ \rm C_3H_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101656-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20212202_Z-20220503101656-1.png"/></alternatives></inline-formula> ion and H atom in the second step is the dominant dissociation mechanism according to the detailed analyses of the Dalitz plot, Newton diagram and <i>α</i> distribution.