Multiwfn forum / Question about comparasion in electron-hole analysis

Re: Question about comparasion in electron-hole analysis

dummy@example.com (sobereva) — Mon, 11 Mar 2024 08:34:33 +0000

Electron-hole analysis only aims at studying radiative transition, in my opinion, it is irrelevant to non-radiative recombination.

Re: Question about comparasion in electron-hole analysis

dummy@example.com (brunosamp) — Sun, 10 Mar 2024 16:00:19 +0000

Mr. tian lu, just one last question. Epoxy groups are known to induce non-radiative recombinations. Electron-hole analysis can show this type of behavior?

Re: Question about comparasion in electron-hole analysis

dummy@example.com (brunosamp) — Tue, 05 Mar 2024 13:59:59 +0000

I understand now, thank you!

Re: Question about comparasion in electron-hole analysis

dummy@example.com (sobereva) — Tue, 05 Mar 2024 02:46:01 +0000

According to Kasha's rule, fluorescence of most molecules (except for very few anti-Kasha molecules, see Chem. Rev. 2017, 117, 13353-13381 and Chem. Rev. 2012, 112, 4541−4568 for reviews) corresponds to emission from S1. It is very common that S1 has a very small or negligible oscillator strength; despite of this, after considering vibronic effect, and/or after long enough time, the emission from S1 is still viable. Before emission from S1, there is usually long enough time to occur sufficient interconversions from high-lying excited states to S1. So, unless you can demonstrate that your molecule doesn't satisfy Kasha's rule, S1 should always be analyzed by Multiwfn to study nature of fluorescence.

Question about comparasion in electron-hole analysis

dummy@example.com (brunosamp) — Mon, 04 Mar 2024 17:36:58 +0000

I have 4 coronene structures. One is only the coronene, and the other 3 are functionalized with: Only an OH groups (Cor-OH); Only an epoxy group (Cor-ep), and only a -COOH group (Cor-cooh).
I want to do a electron-hole analysis to characterize the td-dft absorption bands i obtained (If it's n - > pi*, pi -> pi*).
However, i'd also like to compare how the functional group affects the fluorescence of this structure.
To do so, i wanted to compare the charge density difference isosurfaces, to show the localization of electron and hole, and also the Dindex and transition dipole moment.

My question is: In the Cor-OH groups, the highest oscillator strength is in the S9 excitation, in the Cor-Ep is in the S12 and the Cor-COOH is the S11 excitation. I compared them, and all of them are LE excitations. Can i compare the transition dipole moments and the Dindex to try to compare which structure would have a greater emission in the fluorescence spectra?
Or do i have to pick the same excitation (Ex: The S1 excitation of all structures) to properly compare them? The S1 excitation i obtained for them are not observed experimentally, which is why i'm not using it.