1. Randles-Ševčík Equation
There are many resources that describe the detailed background, derivation, and applications of the Randles-Ševčík equation1-5.
Here, we present just a snippet to get you started.
In a voltammetric experiment where a potential sweep is applied to the working electrode using a potentiostat (e.g., LSV
or CV), the peak current 
observed for a voltammogram follows the Randles-Ševčík equation,
(3)
where is Faraday's constant, is the universal gas constant, is the absolute temperature, is the number of electrons involved in the redox half-reaction being studied, is the diffusion coefficient for the redox active species, is the molar concentration of the redox active species, A is the surface area of the electrode, and \upsilon is the rate at which the potential is being swept.
The Randles-Ševčík equation is often written in an abbreviated form under the assumption that the temperature is fixed at 298.15 K (25℃). For work at this particular temperature, the constants appearing at the beginning of the equation can be combined, allowing the equation to be written more simply as follows:
(4)
The constant appearing at the beginning of this simplified version of the equation is understood to have units (e.g., 2.69 × 105 C mol-1V-1/2).
observed for a voltammogram follows the Randles-Ševčík equation,
(3)
is Faraday's constant, 
is the universal gas constant, 
is the absolute temperature, 
is the number of electrons involved in the redox half-reaction being studied, 
is the diffusion coefficient for the redox active species, 
is the molar concentration of the redox active species, A is the surface area of the electrode, and \upsilon is the rate at which the potential is being swept.
The Randles-Ševčík equation is often written in an abbreviated form under the assumption that the temperature is fixed at 298.15 K (25℃). For work at this particular temperature, the constants appearing at the beginning of the equation can be combined, allowing the equation to be written more simply as follows:
(4)2. References
- Bard, A. J.; Faulkner, L. A.  Electrochemical Methods: Fundamentals and Applications, 2nd ed. Wiley-Interscience: New York, 2000.
- Kissinger, P.; Heineman, W. R.  Laboratory Techniques in Electroanalytical Chemistry, 2nd ed. Marcel Dekker, Inc: New York, 1996.
- Wang, J.  Analytical Electrochemistry, 3rd ed. John Wiley & Sons, Inc.: Hoboken, NJ, 2006.
- Langhus, D. L.  Fundamentals of Electroanalytical Chemistry.  J. Chem. Educ., 2002, 79(10), 1207.
- Elgrishi, N.; Rountree, K. J.; McCarthy, B. D.; Rountree, E. S.; Eisenhart, T. T.; Dempsey, J. L.   A Practical Beginnerâs Guide to Cyclic Voltammetry.  J. Chem. Educ., 2018, 95(2), 197-206.
