Pump-probe NEXAFS (TR-XAS)

Questions
#1

Dear All,

Could you please provide sample input files for
calculating pump-probe NEXAFS (aka TR-XAS) from the S1, S2, T1, T2 states
with EOM-CCSD (and ADC(2))?
We would like to calculate spectra like those shown in Fig. 6 (https://pubs.aip.org/view-large/figure/64968944/024101_1_f6.jpg) of https://doi.org/10.1063/4.0000070 .

Thank you.

#2

Hello Evgenii,
This is not really an appropriate use of this forum, which is dedicated to helping with questions about how to run / use / interpret Q-Chem. Your request is something that should be emailed to the corresponding author on the paper in question.

#3

OK.
I will email the authors.
Thanks.

#4

For TR-XAS with EOM-CCSD, all you need to do is set EE_STATES, CVS_EE_STATES, and CC_TRANS_PROP in the input REM section. Refer to the Manual for detailed explanation of these REM keywords. This will compute oscillator strengths for transitions between all valence- and core-excited states that you have requested. If this doesn’t work, let us know.

#5

Thank you, Kaushik.

Is TR-XAS (PP-NEXAFS) implemented for ADC(2)-x?

#6

Q-Chem has the CVS-ADC(X) method, which you can try. Check out the Manual Example 7.169 here: 7.11.13 Examples‣ 7.11 The ADC( n ) Family of Correlated Excited-State Methods ‣ Chapter 7 Open-Shell and Excited-State Methods ‣ Q-Chem 6.3 User’s Manual. Let us know if there are any issues.

#7

There are a variety of x-ray spectroscopy methods implemented at the ADC, CC, TD-DFT, and DeltaSCF levels. It’s not clear what you mean the time-resolved part of TR-XAS. If it’s electron dynamics that you are interested in, you could use time-dependent Kohn-Sham (TDKS) calculations, also known as “real-time” TD-DFT.

#8

Thank you, @kaushik and @jherbert.

I consider UV/vis pump - X-ray probe scenario.
With EOM-CCSD, I can specify EE_STATES, CVS_EE_STATES, and CC_TRANS_PROP as @kaushik wrote above

Can one do the same with ADC(2)-x?
This means calculate valence-excited states, core-excited state and transitions between them using ADC(2)-x?

Also, with EOM-CCSD I can do a calculation of core-excited states on a MOM SCF reference.
Will this work for ADC(2)-x?

#9

You could also try this.

https://manual.q-chem.com/latest/Ch7.S7.SS3.html
https://pubs.acs.org/doi/full/10.1021/acs.jctc.3c01139

Running some tests for the uracil O K-edge and having partial success.