Fig. 2: KER and reaction pathway of H₃⁺ + C₂H₃⁺ channel.

a Experimental and simulated (red curve obtained by fitting the green bars) kinetic energy release distributions for H₃⁺ channel. b Potential energy curves (PECs) of C₂H₆²⁺ dication as a function of C–C bond length by a rigid potential energy scan. The black curve is the PEC of neutral ethane ground state. The red and blue curves correspond to the PEC of dicationic ethane with dissociation limit CH₃⁺ + CH₃⁺ and CH₂⁺ + CH₄⁺, respectively. c PECs of C₂H₆²⁺ dication as a function of C–C bond length by a relaxed potential energy scan. The sharp peak on the blue curve is due to the relaxation of the proton. d The charge distribution of CH₃⁺ + CH₃⁺ and CH₂⁺ + CH₄⁺ dissociation channel. The solid and dashed curves correspond to the rigid and relaxed potential energy scan. The orange stars come from the AIMD of CH₃⁺ + CH₃⁺. e Potential energy diagrams for the reaction path of C₂H₆²⁺ → H₃⁺ + C₂H₃²⁺ (blue horizontal line) and C₂H₆²⁺ → CH₃⁺ + CH₃²⁺ (red horizontal line). The reaction path of the transition state is confirmed by the IRC calculation and the energies are corrected by the zero-point energy. The blue numbers in e indicate the charge states of CH_n (n = 2, 3, 4). The double ionization energy discrepancies between b, c, and e are due to the potential energy scan without zero-point energy correction in b, c and the relaxation of degrees of freedom invalidate the vertical ionization in c.