Isomerization Dynamics in the Symmetric and Asymmetric Fragmentation of Ethane Dications
Long Wei, C.C. Lam, Yu Zhang, Baihui Ren, Jie Han, Bo Wang, Yaming Zou, Li Chen, Kai‐Chung Lau, B. Wei
Abstract
Hydrogen- or proton-migration-induced isomerization has recently been of concern for its critical role in the dissociation of organic molecules of astrophysical or biological relevance. Herein we present a combined experimental and theoretical study of the two-body C–C bond breakdown dissociation of ethane dication. For the asymmetric fragmentation channel CH2+ + CH4+, the kinetic energy release measurements and ab initio quantum chemical calculations demonstrate that the reaction pathway involving hydrogen-migration-induced isomerization of [CH3–CH3]2+ to [CH2–CH4]2+ can be accessed via the lowest triplet state rather than the ground singlet state of ethane dication. Interestingly, it is found that a considerable proportion of the yield of symmetric fragmentation CH3+ + CH3+, which is usually considered from a direct Coulomb explosion and seemingly independent of isomerization, could come from the dissociation of ethane dication in the ground singlet state with the involvement of [CH3–CH3]2+ isomerization to intermediate [H2C(H2)CH2]2+ of the diborane-like double-bridged structure.