Multiwfn forum

brunosamp

Member

Registered: 2023-04-21

Posts: 18

Question about electron-hole recombination heat map

I want to do a electron-hole recombination heat map for a graphene structure. But i still don't understand the proper calculation to obtain it.
Based on the example provided by the manual, i need to do a TD-DFT calculation asking for a number of states:

Example: m062x/6-31+G(d,p) TD(nstates=n) IOP(9/40=4) and the ground state coordinates of my optimized molecule

The formchk of this calculation will be enough to obtain the heat map or i need to do another calculation?

Second question: Would the diffuse function of my method bring any sort of problems to obtain my heat map?

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,763

Website

Re: Question about electron-hole recombination heat map

You can plot the heatmap based on .fchk file (obtained by formchk) and Gaussian output file, as illustrated in Section 4.18.2.2 of Multiwfn manual.

Diffuse functions may be used for this purpose. However, note that in most cases, diffuse functions do not bring any advantage.

brunosamp

Member

Registered: 2023-04-21

Posts: 18

Re: Question about electron-hole recombination heat map

Thank you sir, i was able to do it!
Just one more question, if i may. I have 5 graphene based structures, with slight structural differences (one has a hydroxyl group, another a carboxyl group, etc.). Each one of them has a different absorption range, which means that each structure has a different excited state with higher oscillator strength.
Can i compare all these structures using different excited states, or i'd need to use the same excited state, always?

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,763

Website

Re: Question about electron-hole recombination heat map

If you hope to study the nature of a prominent absorption peak, usually you can check oscillator strength to identify the index of the excited state that maximally contribute to the peak, and then you can perform various analysis on that excited state via Multiwfn.