Hydrogen migration in Coulomb explosion of cyclohexane to C2H4+ and C4H8+: Theoretical and experimental studies

Abstract

AbstractThe equilibrium structure of cyclohexane dication C6H122+ and singly charged ions C2H4+ and C4H8+ suggests that hydrogen migration can proceed in dissociation process of C6H122+ to C2H4+ and C4H8+. Using dc‐slice imaging technique, the fragmentation pathway C6H122+ → C2H4++C4H8+ is detected under an intense femtosecond laser field. Two‐body Coulomb explosion (CE) of C6H122+ to C2H4+ and C4H8+ is securely identified. The quasi‐isotropic distributions of ions indicate the precursor have a relatively long dissociation time. Then, B3LYP density functional theory calculations are performed on this dissociation process, the results show the precursor C6H122+ undergoes molecular rearrangement and 1, 2‐ and 6, 5‐ hydrogen migrations during the dissociation process. These molecular rearrangement and hydrogen migration processes can reduce the anisotropy distribution of fragment ions C2H4+ and C4H8+, which is consistent with the experimental results. The present work will be useful to understand hydrogen migration processes within the hydrocarbon molecules.