Hydrogen migration in Coulomb explosion of cyclohexane to C2H4+ and C4H8+: Theoretical and experimental studies. Issue 22 (23rd July 2018)

• Record Type: Journal Article
• Authors: Wu, Hua; Wang, Hui; Guo, Zihan; Wen, Junqing
• Is Part Of: International journal of quantum chemistry. Volume 118:Issue 22(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-07-23
• Subjects: ab initio calculation -- Coulomb explosion -- femtosecond laser pulses -- hydrogen migration; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.25764
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: The equilibrium structure of cyclohexane dication C6 H12 2+ and singly charged ions C2 H4 + and C4 H8 + suggests that hydrogen migration can proceed in dissociation process of C6 H12 2+ to C2 H4 + and C4 H8 + . Using dc‐slice imaging technique, the fragmentation pathway C6 H12 2+ → C2 H4 + +C4 H8 + is detected under an intense femtosecond laser field. Two‐body Coulomb explosion (CE) of C6 H12 2+ to C2 H4 + and C4 H8 + 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 C6 H12 2+ 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 C2 H4 + and C4 H8 +, which is consistent with the experimental results. The present work will be useful to understand hydrogen migration processes within the hydrocarbon molecules. Abstract : The equilibrium structure of cyclohexane dication (C6 H12 2+ ), and singly charged ions C2 H4 + and C4 H8 +, indicates that hydrogen migration may be involved in photofragmentation of C6 H12 2+ to C2 H4 + and C4 H8 + . Quantum chemical calculations on this pathway show that C6 H12 2+ undergoes 1, 2‐ and 6, 5‐H migrations before dissociating into C2 H4 + and C4 H8 + . The almost isotropic distribution of CE channel of C2 H4 + and C4 H8 + obtained by dc‐slice imaging technique supports these theoretical results.