where 𝜉 and 𝜒 contain all parameters independent of cations. Using the measured |𝜎| and reported values of ∆𝐺 /0& to fit 𝑗 '%( , we obtain a linear relation as theoretical prediction with a R 2 value of 0.96 (Fig. ). The excellent agreement between experimental data and theoretical deduction supports the reasoning discussed above that the electronic coupling for ET and vibrational coupling for PT can be described by |𝜎| and ∆𝐺 /0& , respectively. A 𝜉 value of 0.005 mA μC -2 cm 2 is obtained from the linear fitting (Fig. , related parameters employed in the fitting summarized in Table ), which leads to the 𝐻 78 value of 0.36 ~ 1.06 cm -1 with various cations (Table ). It is consistent with the nonadiabatic ET, satisfying the basic assumption of the PCET theory . 𝜒 is fitted to be 0.38 eV -1 , which corresponds to a proportionality coefficient 𝛾 of 0.007. This indicates that 0.7% part of ∆𝐺 /0& contributes to the interaction energy of cation with the R-mode, which implies the validity of considering the influence of cations on the harmonic oscillator of R-mode as a small perturbation. We note that although the values of 𝐻 78 and 𝛾 vary slightly depending on the choice of values of the parameters in Table , these variations do not change the overall insights gained in this analysis.