Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly  
We are NATO-free zone

Re^3: Can't figure out how to find emission spectra of Benzene...

Pavlo Solntsev

I attached example how to do Luminescence calculation for porphyrin molecule. For more detailed information please, check manual AND this forum.

Salvation model has not been programmed for TDDFT+gradient. Therefore, optimization of the excited state was done without solvent correction. However, this correction was included into spectra calculation.

Very often geometry optimization of the excited state brakes a true molecular symmetry. Keep this in mind.

For more complex systems state of interest may be different, not S1. It is especially true if you have a donor group in your molecule and thus HOMO....HOMO-x belong to the donor, but you are looking for emission within porphyrin core. In such case you need identify the state of interest based on TDDFT(ground state) and knowledge.

Good luck.


On Tue Jun 10 '14 10:16pm, Siddheshwar Chopra wrote
>Dear Alex,
>I searched a lot on this forum regarding the same. What you told is right and I know these too. But I want to step by step how to optimize  the S1? say for  benzene.
>And then how should I determine S0--> S1 (optimized)?
>Please help me stepwise. Any i/p files would be of great help.. I have noted from TDDFT calc of benzene that orbitals 17-24 are most dominant ones. How do I proceed next?

>Kind Regards,

>n Tue Jun 10 '14 7:43pm, Alex Granovsky wrote

>>for emission spectra you need to optimize S1 geometry and then compute
>>vertical transition from S0 to S1 at optimized geometry of S1.

>>Kind regards,
>>Alex Granovsky
>>On Sat Jun 7 '14 9:10pm, Siddheshwar Chopra wrote
>>>Dear Firefly users,
>>>I need some real help in determining the emission spectra (S1--->SO*) of benzene.
>>>I have understood till optimizing the ground state and then obtaining the vertical transition from SO--->S1*...
>>>Please help me now what I should do next? Any i/p files would be welcomed.

>>>Kind Regards,

This message contains the 4014 kb attachment
[ luminescence.tar.gz ] INPUT and OUTPUT files for luminescence

[ Previous ] [ Next ] [ Index ]           Wed Jun 11 '14 4:17pm
[ Reply ] [ Edit ] [ Delete ]           This message read 537 times