Redox potentials measure how easy or hard it is to add or remove electrons from an atom. To remember the difference between reduction and oxidation, you can use “OIL RIG”: Oxidation Is Loss (of electrons) and Reduction Is Gain (of electrons).
Rowan's redox potential prediction workflow quickly predicts redox potentials using either GFN2-xTB and the CPCM-X solvent model (rapid mode) or B3LYP and the CPCM solvent model (careful mode).
Rowan optimizes the neutral, oxidized, and reduced structures and adds a solvent correction using the new CPCM-X method from Grimme and co-workers to get better free energies of solvation (or, when running this workflow in careful mode, the CPCM solvent model).
When the workflow is finished, Rowan lets you view the reduction and oxidation potentials relative to different reference electrodes, using conversion constants from Pavlishchuk and Addison.
On the OROP benchmark set, Rowan's redox potential prediction workflow (in rapid mode) displays a mean absolute error of 0.32 V (excluding a few values that don't start from a neutral species or aren't in acetonitrile).
Rowan's redox potential prediction workflow can be run in two modes: rapid or careful. Here's what selecting each mode tunes:
| Mode | Rapid | Careful |
|---|---|---|
| level of theory | GFN2-xTB/CPCM-X | B3LYP/CPCM |