## Square Wave Voltammetry Simulation

smaerd - 25-12-2015 at 18:11

Because, I always thought electrochemistry was Oh-So-Fascinating I learned some of it's basic principles/applications. Interestingly electrochemistry is one of the types of chemistry which can be modelled quite easily and 'well' via simulation. One of my favorite applications is Square-wave Voltammetry (SWV). .

In the holiday spirit I figured I'd share some code with you all .

Here's a SWV simulation function written in R which I adapted from a publication written in MATHCAD (Bulletin of the Chemists and Technologists of Macedonia, Vol. 18, No. 1, pp. 57–64 (1999)). Keep in mind this simulation is not the complete story and exhibits a good deal of simplifications/approximations but it's good enough to get the ball rolling.

Attachment: square.wave.R (3kB)

I am also including a few small examples which demonstrate how the function can be used. The first uses the same kinetic parameters except changing diffusion based mass transfer (diffusion constant) in situations of say increasing binary solvent concentration.

Attachment: diffusion tests2.R (845B)

The second examines the effect of charge transfer coefficient (α) and heteregeneous rate constant (k) on peak current. This is a simple theoretical way to try to find scan-rates that will produce quantitative data from peak current (height) in many samples with different environments/conditions.

For the uninitiated this simply means that the kinetic parameters (α, k) both change the observed peak height(amps) for a given analyte. Interestingly, these parameters are also effected by the scan rate (volts/second). So if there is a range of kinetic parameters where the peak current is effectively constant (flat) then the scan rate which induces the kinetic parameters to be in the constant "domain" is ideal for use to obtain quantitative information.

Attachment: K and alpha variance on current.R (3kB)