Transient Absorption Calculations

Er_BELOKI

Dear fellow scientists,

First, sorry if this post is repeated. It is quite complicated to search posts with the automatic translation from Chinese to English.

I am Jose I am a chemist with background is in spectroscopy, mainly in Transient Absorption Spectroscopy (TAS). But I would like to expand my knowdlege and to try to dive into the world of theoretical calculations. I have done some in the past, but very superficial ones.

If you don′t know, TAs is a technique where, in short, a laser excites the sample, to obtain the excited states, and other part of the laser probes those excited states measuring their absorbance. This means, you obtain the spectra of the excited states (this can be singlets, triplets, CT states, etc).
I would like to run similar calculations to a TD-DFT but to those excted states to have the TD-DFT of the S1, S2, T1, etc...
For those, I think I should optimise the excited states, but I don′t know how to do it, or which keyword is needed.

I have access to Gaussian 16 and I have done previous calculations of Raman spectra, TD-DFT, optimisations, etc...

Thanks for your help!!

sobereva

Rigorously calculating Transient Absorption Spectroscopy is never easy. You may check J. Comput. Chem., 43, 1641–1655 (2022), which provides a code for this purpose.

PS: You are welcomed to post fully in English, translating via AI is not needed. Anyone in this forum that can reply your questions must have a good English reading skill.

Er_BELOKI

Thanks a lot Professor.
I will have a look on that paper!