CV: Determine half-peak redox potentials in ChemSpectra

I am an ELN admin and user

Is your enhancement request related to a problem? Please describe. Researchers do CV measurements and get CV spectra with reversible signals. However, some chemists aren't that lucky but often observe irreversible redox events i.e. the duck sleeps and is hiding its head below its feathers, plus might sleep on its back.

While determination of the half-wave potential E_1/2 are usually done for reversible redox events by averaging the forward and reverse peak potentials, this is not possible for irreversible oxidations or reductions. One way out is to determine the half-peak potential E_p/2, which is quiet accurate as e.g. shown in https://doi.org/10.1055/s-0035-1561297 .

Determination of the half-wave potential E_1/2 is already possible in ChemSpectra. Great feature! Thank you for that! As the inline notation should be generated by ChemSpectra at some point, also half-peak potential E_p/2 should be able to be determined with ChemSpectra.

The current workaround is to pick the peak potential E_p with its peak current I_p. Then check the potential at the half-peak current I_p/2. This potential is the half-peak potential E_p/2, which should be reported. However, in ChemSpectra this is listed in the table in "ox" for negative potentials and "red" being on the side of positive potentials. To get the E_p/2 to the E_1/2 column, one could iteratively shift "ox" (or "red") until until this value is shown in the E_1/2 column. I added a Video to illustrate this:

https://github.com/ComPlat/chemotion_ELN/assets/85482437/491c4a57-42d2-43e4-92a8-94b218b7290e

The table also provides ΔE_p for this, which does not make sense. One could report the half-peak current I_p/2 instead, but the values of the currents depend on scan rate as well as concentration. Currently, I would stat that it does not make any sense to report this.

Describe the solution you'd like Users should be also able to determine half-peak potentials E_p/2. Initially, the table needs another column with label E_p/2.

Next to the little green+ sign, to add another line to the table, there should be a label "E_1/2" to generate a new line as it is currently generated.

Next to this little green + sign, should be another green + sign with label "E_p/2". If this is pressed, a new line in the table is generated. Users then may select "Ox" or "Red", depending on which side of the ordinate (y-axis) they are and pick a peak with its peak potential E_p and peak current I_p. The other field "Ox" or "Red" should stay empty or "nb", respectively.

Then, the the field in the column E_p/2 should be automatically filled with P = I_p/2 = I_p / 2. No ΔE_p needs to be calculated i.e. the corresponding field in the column should stay empty or with "nd".

Best, Tillmann

ComPlat / chemotion_ELN

CV: Determine half-peak redox potentials in ChemSpectra #1739