09143 IUPAC Gold Book - Randles–Ševčík equations 10.1351/goldbook.09143 09143 current 1 Equations describing the peak current \(I_{\rm{p}}\) in linear scan voltammetry and cyclic voltammetry as a function of the amount concentration, \(c_{\rm{0}}\), of electroactive species in bulk solution. For a reversible charge transfer: \[I_{\rm{p,rev}} = k\,z\,F\,A\,c_0 (z\,F\,D\nu/RT)^{1/2}\] for irreversible charge transfer: \[I_{\rm{p,irrev}} = k^{\prime}(\alpha z^{\prime})^{1/2} zFA{c_0}(FD\nu/RT)^{1/2}\] where \(k\) and \(k^{\prime}\) are numerical constants, \(\alpha\) is the charge transfer coefficient (usually assumed to be close to 0.5), \(z\) the electron number of an electrochemical reaction, \(z^{\prime}\) the number of electrons transferred before the rate determining step, \(F\) the Faraday constant, \(R\) the gas constant, \(T\) the thermodynamic temperature, \(A\) the electrode surface area, \(D\) the diffusion coefficient, and \(\nu\) the scan rate. For \(A\) in \(\pu{cm2}\), \(D\) in \(\pu{cm2 s-1}\), \(\nu\) in \(\pu{cm2 s-1}\), and \(c_{0}\) in \(\pu{mol cm-3}\), and \(I_{\rm{p}}\) in \(A\). At \(T = \pu{298.15 K}\), for reversible charge transfer \(k = 0.446\), and for irreversible charge transfer, \(k^{\prime} = 0.496\). cyclic voltammetry https://goldbook.iupac.org//terms/view/09134 electron number of an electrochemical reaction https://goldbook.iupac.org//terms/view/09063 linear scan voltammetry https://goldbook.iupac.org//terms/view/09141 PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 677 (https://doi.org/10.1515/pac-2018-0109) https://goldbook.iupac.org/terms/view/09143/html https://goldbook.iupac.org/terms/view/09143/json https://goldbook.iupac.org/terms/view/09143/plain Citation: 'Randles–Ševčík equations' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09143 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-04-18T09:27:28+00:00