cathodic transfer coefficient, αc

For a reaction with a single rate-determining step

$Math - e$

where $Math - text$ is the cathodic transfer coefficient (number), $Math - text$ is the gas constant, $Math - text$ is the thermodynamic temperature, and $Math - text$ 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 $Math - text$ electrons.

Source:

PAC, 1974, 37, 499 (Electrochemical nomenclature) on page 515