= Tafel slope
{c}
{title2=$b$}
The change in <overpotential> per decade of <current density> in the activation-controlled regime of a <Tafel equation>. In a single-step <Butler-Volmer equation> with constant transfer coefficient, the anodic slope is $b_a=RT\ln10/(\alpha_a nF)$, where $T$ is <temperature>, $R$ is the <molar gas constant>, $n$ is the number of transferred <electrons> and $F$ is the <Faraday constant>. The magnitude of the cathodic slope is $b_c=RT\ln10/(\alpha_c nF)$. Inferring one from the other requires the model's relation between the two coefficients; the equality $\alpha_a+\alpha_c=1$ applies to this effective single-step model and need not describe a multistep reaction.
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