Dear Nitika Grover ,

If I remember well, it is quite easy to calculate redox potentials at the ground-state and extrapolate at the excited-state of interest using the energy of excitation (experimental or obtained by theory).

For this purpose, you will need to implement your Born-Haber thermodynamical cycle and consequently calculate the energy and Gibbs free energy (with the correction with the temperature) for your molecule before oxidation or reduction (depending on what you want, either oxidation or reduction), your radical anion (or radical cation) in gaz phase and then in solvent.

You then used the Nernst equation to obtain your potential from your ∆Gox(solv) or ∆Gred(solv) calculation.

You then remove the E_{0-0} energy from your oxidation potential obtained at the ground-state to obtain your ∆Gox(solv)* at the excited state. Or you add this E_{0-0} energy from your reduction potential ground-state to obtain your ∆Gred(solv)* at the excited-state.

I think you might find useful this publication in which they explain the procedure to calculate the redox potential at the ground-state.:

https://pubs.acs.org/doi/10.1021/jp4062412

I remember I obtained very close excited-state potentials for organic molecules in the past (error ~ 0.1-0.3 V compared to experimental). Yet, I don't have experiences when this calculation is carried out with a metal centre.

Hope my answer will help you!

K. Kalyanasundaram Phochemistry of Polypyridine and Porphyrin Complexes 1992