Can Dalton use TDDFT to search the geometry of an excited state?

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xiongyan21
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Can Dalton use TDDFT to search the geometry of an excited state?

Post by xiongyan21 » 21 Jul 2020, 08:24

Can Dalton use TDDFT to search the geometry of an excited state by which fluorescence can be calculated?
I previously used GAMESS to have found that of thibendazole in methanol step by step, without imaginary frequencies in gas and methanol, respectively, and found the emission wavelength can be compared with what was reported in an journal articl;the oscillators strength calculated also supports fluorescence which can be detected.

Very Best Regards!
Last edited by xiongyan21 on 29 Jul 2020, 01:09, edited 3 times in total.

cymantren
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Re: Can Dalton use TDDFT to search the geometry of an excited state?

Post by cymantren » 23 Jul 2020, 15:00

Dear Yan,

as far I know it is not possible to use TDDFT with DALTON or LSDALTON, but I am not really sure. According to the dalton-manual, one can however use
....
*RESPONSE
.TDA Invoke the Tamm-Dancoff approximation to RPA/TDHF or TDDFT. Equivalent to
the use of .CIS on a Hartree-Fock calculation.
....

In both manuals II did'nt find anything about it, expect the above mentioned entry.
Best greetings

Alfred

kennethruud
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Re: Can Dalton use TDDFT to search the geometry of an excited state?

Post by kennethruud » 23 Jul 2020, 20:34

Dalton cannot in the current release calculate excited-state DFT geometries, but this should be possible with LSDalton, and the test case geomopt/Excited_state_opt should show how this can be done, according to the LSDalton 2018 manual: https://daltonprogram.org/manuals/lsdal ... manual.pdf

Alternatively, depending on the size of the molecule, you can do excited-state optimizations using MCSCF program, explicitly selecting the excited state of interest.


Best regards,

Kenneth

xiongyan21
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Re: Can Dalton use TDDFT to search the geometry of an excited state?

Post by xiongyan21 » 24 Jul 2020, 05:06

Dear Prof. Ruud
I am using GAMESS in this way to calculate fluorescence of pesticides and organic molecules, and in the spin-flip fashion to do phorsphorescence of them.
If possible, I will compare the results with those from Dalton2018.

Very Best Regards!

kennethruud
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Re: Can Dalton use TDDFT to search the geometry of an excited state?

Post by kennethruud » 24 Jul 2020, 07:30

Thanks for the info. In relation to this goal, I should then add that to the best of my knowledge, LSDalton would not be able to optimize the geometry of an excited triplet state, this is not implemented, I believe, and you are then left with MCSCF as an option.

Having said this, if you have the excited-state structure from some other source, Dalton can calculate phosphorescence lifetimes to that excited state from the corresponding ground-state geometry using quadratic response theory, as described in the manual.


Best regards,

Kenneth

xiongyan21
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Re: Can Dalton use TDDFT to search the geometry of an excited state?

Post by xiongyan21 » 24 Jul 2020, 07:47

Dear Prof. Ruud
It sounds interesting.
Very Best Regards!

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