𝑉 /+ is the vibronic coupling between the ground vibronic state of the reactant and the product vibronic state 𝜈 with the dominant contribution to the rate constant. Then the partial current density of CO, 𝑗 "# , can be expressed as: which is Eq. 2A in the main text used to fit 𝑗 "# -𝐸 curves in Fig. and.