Question on visualizing PET mechanism with Gaussian and Multiwfn

moiumuio

Hi everyone,
I have studied photoinduced electron transfer (PET) through Gaussian and Multiwfn. Although I could prove that PET occurred from the experiment, I cannot prove that from a theoretical calculation.
I have optimized the complex (Fluorophore (F)+Quencher(Q)), then calculated vertical excitation, but I saw no electron transfer from Q to F from the visualization tool from Multiwfn.
What process should I do?
Thank you

sobereva

There are many possible reasons. For example, there are local excitation (LE) states on each fragment, and CT states corresponding electron transfer between the two fragments; if you only selected LE state to study, obviously you cannot observe electron transfer from e.g. hole-electron analysis or IFCT analysis in Multiwfn.

moiumuio

sobereva 发表于 2025-7-19 05:12
There are many possible reasons. For example, there are local excitation (LE) states on each fragmen ...

Dear Prof.,
I have selected the first 5 states for studying. Usually, for dynamic PET (LUMO of Q instead of HOMO), the first or second state is the CT state, but I cannot see that with this. Are there any other ways to check that?
I am pretending to do relaxation excitation, is it good to do that?
Thank you.

sobereva

moiumuio 发表于 2025-7-19 17:20
Dear Prof.,
I have selected the first 5 states for studying. Usually, for dynamic PET (LUMO of Q ...

If "relaxation excitation" means optimizing excited state, you may have a try.
Also you can check higher-lying excited state. Using the IFCT function illustrated in Section 4.18.16 of Multiwfn manual, you can very easily obtain amount of charge transfer between two defined fragments, thereby very straightforwardly identifying the CT state of interest.