Multiwfn forum

wham09

Member

Registered: 2025-09-19

Posts: 44

visualizing exchange and correlation holes in sobEDA framework

Dear Prof. Lu,

I am wondering if I could somehow monitor the electron density change over the course of sobEDA steps so that I could separately examine exchange and correlation effects. Changes beginning from the promolecular state should be trivial, I would just have to substract e-density function between promol/frozen and frozen/final.

But ideally, I also want to dissect the first step (fragments to promolecular) into multiple different electronic structures to separate electrostatic, exchange, correlation, and dispersion effects on the electron density. What I could think of is repeating the fragment-to-promolecular step 1) with HF level, and 2) with the original level but without DFT-D3. (Original level I used for the whole sobEDA was PBE0-D3(BJ)/ma-TZVP).

Please let me know if this whole thing is just a stupid idea, or if it might be possible in a more sophisticated manner. Thank you very much!

sobereva

Tian Lu (Multiwfn developer)

From: Athens, Greece

Registered: 2017-09-11

Posts: 2,171

Website

Re: visualizing exchange and correlation holes in sobEDA framework

Hi,

Dispersion effect of sobEDA is considered based on DFT-D3 dispersion correction, which doesn't affect electron density but only affects potential energy surface.

Classic electrostatic interaction doesn't affect electron density, it is a energetic term calculated based on existing charge distribution.

In the process of occurrence of interfragment interaction, it is well-known that only steric effect (mostly corresponding to repulsion and exchange terms) and polarization effect (corresponding to orbital interactions) notably change electron density, the two parts can be separatedly characterized in ETS-NOCV analysis, which can be easily realized by Multiwfn. Please check Section 3.26 of Multiwfn manual for theoretical background and Section 4.23 for abundant examples.

Best regards,

Tian Lu