## cathodic transfer coefficient, $$\alpha_{\text{c}}$$

https://doi.org/10.1351/goldbook.C00906
For a reaction with a single rate-determining step $\frac{\alpha _{\text{c}}}{\nu } = -\frac{R\ T}{n\ F}\ (\frac{\partial (\ln (|I_{\text{c}}|))}{\partial E})_{T,p,c_{i},...}$ where αc is the cathodic transfer coefficient (number), R is the gas constant, T is the thermodynamic temperature, and ν the stoichiometric number giving the number of identical activated complexes formed and destroyed in the completion of the overall reaction as formulated with the transfer of n electrons.
Source:
PAC, 1974, 37, 499. 'Electrochemical nomenclature' on page 515 (https://doi.org/10.1351/pac197437040499)