Multiwfn forum

brunosamp

Member

Registered: 2023-04-21

Posts: 18

Multiwfn can analyze the orbitals involved in each UV/transition?

I am trying to analyze the orbitals that are involved in the absorption transitions of my TD-DFT analysis.
I used m062x/6-31G(d,p), under TD-DFT, to obtain the absorption spectrum of my molecule.
But i want to analyise, for example, if the transition in a certain wavelength is of the type "n->pi* or "pi->pi*".
Can the multiwfn do this type of analysis?

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,830

Website

Re: Multiwfn can analyze the orbitals involved in each UV/transition?

There are many different ways. For example, if there is a dominant MO transition for the studied excited state, you can simply use main function 0 of Multiwfn to visualize the two oribtals to assign the transition character. If there is no dominant MO transition, you can use Multiwfn to obtain natural transition orbitals (NTO) and visualize the NTOs to determine transition character, see Section 4.18.6 of Multiwfn manual for example. Also hole-electron analysis illustrated in Section 4.18.1 is quite useful, and it is much more universal than NTO analysis.

If you don't understand which electron excitations notably contribute to the absorption peaks and thus should be subjected to above analyses, when you use Multiwfn to plot UV-Vis spectrum, you can decompose the spectral curve to individual contributions from various electron excitations, see Section 4.11.2 of Multiwfn manual for example.

brunosamp

Member

Registered: 2023-04-21

Posts: 18

Re: Multiwfn can analyze the orbitals involved in each UV/transition?

Thank you very much for your help, Mr. Tian Lu!