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

[xiongyan21]

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, and found the emission wavelength can be compared with what was reported in an journal article; the oscillators strength calculated also supports fluorescence which can be detected.

Very Best Regards!

[cymantren]

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]

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]

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]

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]

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