Multiwfn forum

Egery

Member

Registered: 2023-11-21

Posts: 2

About oscillator strength in UV spectrum in Wultiwfn

Good time of day. I provided my computations in ORCA 5.0. I have the following question about oscillator strength in UV spectrum in Wultiwfn. I want to know how to display oscillator strengths in the program which correspond to the maximal wavelengths because it is very important in investigations of dyes. Since it is just displayed Molar absorption coefficient and wavelength without oscillator strengths after the following commands.

11 // Plot spectrum
3 // The type of the spectrum is UV-Vis
15 // Output the spectrum including the contributions from certain individual transitions
0.01 // The criterion of selecting transitions is oscillator strength > 0.01

And also file spectrum_line.txt doesn't help me to find out precise values of oscillator strengths corresponding to the maximal wavelengths.
What may you advise me in this question?

Thank you!

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,624

Website

Re: About oscillator strength in UV spectrum in Wultiwfn

From theoretical calculation view point, there is no concept of oscillator strength (f) of an absorption peak. f is directly calculated for each electronic excitation via e.g. TDDFT, EOM-CCSD.

However, it is in principle possible to fit f for experimentally observed or theoretically simulated absorption peak, you need to use such as Origin to perform the fitting. See J. Phys. Chem. A, 126, 435−443 (2022) for discussion.

PS: It is not Wultiwfn but Multiwfn.

Egery

Member

Registered: 2023-11-21

Posts: 2

Re: About oscillator strength in UV spectrum in Wultiwfn

Professor, Tian Lu. Thank you very much for your answer and for your help. Your program(Multiwfn) is amazing!