Sequential deprotonation of the allene trication produced by 30-keV/u <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi mathvariant="normal">He</mml:mi><mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math> impact
Zhencen He, Jiarong Wang, Yu Zhang, Bo Wang, Jie Han, Baihui Ren, Long Wei, Zihan Xia, Pufang Ma, Tianming Meng, Yaming Zou, Zhimin Hu, B. Wei
Abstract
The three-body fragmentation channel ${\mathrm{H}}^{+}+{\mathrm{H}}^{+}+{\mathrm{C}}_{3}{\mathrm{H}}_{2}{}^{+}$ of the allene trication produced by 30-keV/u ${\mathrm{He}}^{2+}$ ion impact is investigated using cold-target recoil-ion momentum spectroscopy. The two protons with different kinetic energies are found emitted sequentially from the parent trication. The presence of such a sequential deprotonation process and the absence of corresponding concerted deprotonation may result from a major molecular deformation process, e.g., ultrafast hydrogen migration, which occurs in the parent ion prior to fragmentation, and finally leads to the formation of two different protons.