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Re^7: Regarding the CITYP=TDDFT calculation for the excited state

Alex Granovsky

Dear Siddheshwar,

It is not possible to obtain this information directly from the
spectra. You need to examine orbitals or at least to check their
symmetry type.

Kind regards,
Alex Granovsky

On Sat Aug 30 '14 4:15pm, Siddheshwar Chopra wrote
>Dear Alex,
>I skipped the notation for triplet states.. :-) Thanks for reminding me.
>Sir I have understood till finding the dominant transitions and visualization of those orbitals.. But I want to understand from the point of view of pi-pi* transition etc for prominent parts of the spectra. Say lambda-max is 300nm.. corresponding to orbital homo+1------> lumo+2 transition. I have understood the energywise preferences of pi-pi* etc transitions, but i want to know how do i pick this information directly from the firefly output or the spectra?

>Kind Regards,
>On Sat Aug 30 '14 3:31pm, Alex Granovsky wrote
>>Dear Siddheshwar,

>>In S0 and S1, "S" stands for "singlet". For triplet states the
>>notation is T0, T1, etc... Firefly only supports TDDFT computations
>>on triplet states using singlet reference. This means that the lowest
>>triplet state computed in TDDFT for triplets is T0 and the next is T1
>>Thus, unlike singlet states, in the case of triplets, ISTATE=1
>>corresponds to T0 i.e. the lowest triplet state and ISTATE=2
>>corresponds to T1.

>>As to analysis if transitions, one of the way is the visualization
>>of orbitals with dominant contributions to transitions. In addition,
>>Firefly computes CIS and TDDFT natural orbitals which may be of help
>>for your purposes.

>>Kind regards,
>>Alex Granovsky
>>On Thu Aug 28 '14 1:29pm, Siddheshwar Chopra wrote
>>>Dear Alex,
>>>Your confirmation means a lot. Thank you again. What you told is about the singlet state. What if the SO and S1 both are triplets and we want to study S1---->SO transition now?
>>>Also from the output file of TDDFT calculations, we can know the dominant transitions. But is there a way to discuss these transitions in terms of pi, sigma bonding or antibonding orbitals? Is there any other software to do this job or any command we can add to do it?
>>>On Tue Aug 26 '14 7:38pm, Alex Granovsky wrote
>>>>Dear Siddheshwar,

>>>>For singlet states, ISTATE = 1 corresponds to S1 state i.e to the first singlet excited state.

>>>>Kind regards,
>>>>Alex Granovsky
>>>>On Tue Aug 26 '14 7:17pm, Siddheshwar Chopra wrote
>>>>>Dear Alex,
>>>>>Thank you for the information. ISTATE as I know is for the singlet state.
>>>>>But still my doubt is not clear. I want to know that does using cityp=tddft, runtype=optimize actually optimizes FIRST OR LOWEST GROUND STATE? If,yes then how do I ensure that it is the first excited state only. After optimization, what I get is the optimized coordinates...but I am unsure about whether they belong to first excited state or not.
>>>>>The final aim is to find vertical transition from this state to the gnd state.


>>>>>On Tue Aug 26 '14 4:13pm, Alex Granovsky wrote




>>>>>>is enough. You can omit the second line as ISTATE is set to one by default.

>>>>>>To turn state tracking on for the first excited state, use:



>>>>>>Kind regards,
>>>>>>Alex Granovsky
>>>>>>On Tue Aug 26 '14 1:18pm, Siddheshwar Chopra wrote
>>>>>>>Dear Users,
>>>>>>>I wish to know Does using "CITYP=TDDFT RUNTYP=OPTIMZE" optimize the lowest (first) excited state? How do I ensure the same? I used the optimized S0 geometry for this run with state tracking on.


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