Siddheshwar Chopra
sidhusai@gmail.com
Please help me understand this.
Kind Regards,
On Fri Jun 20 '14 2:42pm, Pavlo Solntsev wrote
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>On Fri Jun 20 '14 1:01pm, Siddheshwar Chopra wrote
>--------------------------------------------------
>>Dear Pavlo,
>>Thanks for the useful answers. I have some points:
>>1) I will then keep the state tracking on always. however I dont know how to track this flipping of states manually. I came to know of tdprp=.t., to get excited state properties. Is it good to try??
>There is no option to track a state manually, AFAIK. About TDPRP, it is always good to try.
>
>
>>2) Regarding B3U.. i used gausssum... with no symmetry constraint...
>gausssum is basically a wrap for cclib. It reads information from you output file. In you output file your molecule has C2 symmetry.
>>3) Thanks for the docs.zip.
>>4) regarding mcscf one... Pavlo I am actually interested in fluorescence only... so I think state tracking won't be essential in my case.. what do u say?
>It is important for geometry optimization of an excited state. Different systems, different situation. I know system where you have to optimize state #17 to get luminescence.
>>5) One most important question to u: Is it the same way I should check for imaginary frequencies for the S1* state, like we do for S0?? I must run hessian for every optimization right?
>Technically- yes.
>>kind Regards,
>>On Tue Jun 17 '14 2:58pm, Pavlo Solntsev wrote
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>>>On Tue Jun 17 '14 1:25pm, Siddheshwar Chopra wrote
>>>--------------------------------------------------
>>>>Dear Pavlo,
>>>>I really appreciate all your help. Your guidance has helped me a lot always.
>>>>Sir, regarding you replies:
>>>>1) regarding state tracking... do you mean to say if i m studying singlet to singlet transition, then it is not necessary??
>>>No.It just help you to track (watch) the state of interest if order of states changes during the geometry optimization. I believe the optimization of triplet state should be the same as singlet.
>>>>In general can I take it as a rule of thumb to switch it on always?? Like you did..
>>>>I just need to add - sign to activate it..and then i dont need to bother about anything else right??
>>>It is make sense for geometry optimization only. Yes, it is safe to leave it on.
>>>>2) I understood about using optimized coords. Of S0 for S1*.. thnx for that..
>>>>But how did you know B3U is first excited state? I checked my o/p file with gausssum.I couldn't get that information.. i could only find A and B..
>>>What is the point group of porphyrin? Gaussian used C2 group. It is problem with Gaussian.
>>>>3) Regarding PCM... i checked 8.0.x manual.. but couldnt find the list of solvents.. :-(
>>>http://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.ziphttp://classic.chem.msu.su/gran/gamess/docs.zip
>>>>4) Pardon me about the last one... I am unsure about it as I read in this forum that active space is created.. yes it is not dft..it is MCSCF/XMCQDPT2...
>>>>I just wish that the procedure you have told me will be the best suited for my needs.. :-)
>>>>Pavlo following the same procedure, I can get singlet to either singlet or triplet transitions/emission spectra..right? But then for downward transitions, the gnd state multiplicity will change..
>>>Probably it is correct to talk about phosphorescence. If you optimized triplet state and then looking for transition to a singlet.
>>>Pavel.
>>>>Kind Regards,
>>>>
>>>>
>>>>On Mon Jun 16 '14 9:18pm, Pavlo Solntsev wrote
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>>>>>On Mon Jun 16 '14 11:00am, Siddheshwar Chopra wrote
>>>>>---------------------------------------------------
>>>>>>Dear Pavlo,
>>>>>>Sorry for replying late. I just went through all the files you had provided. I am really grateful to you for taking out time to make us understand this so well. I am really thankful to you.
>>>>>>Pavlo I checked all the files and would be glad if you could answer some basic questions:
>>>>>>1) The emission spectra is obtained from the file "pp_opt_s1_tddft.out"?
>>>>>Yes
>>>>>>2) From S1*--> S1... How to use and understand state tracking? I actually don't understand what I am supposed to do with it. I just know how to turn it on. What happens if I switch it off?
>>>>>In example i gave you, state tracking probably doesn't matter. However, if you want to relax say state #3 then it may be swapped with other state. In that case state tracking should be turned on. See $TDDFT ISTATE $END description.
>>>>>>3) You said "1st excited state is B3U"...and used the same optimized coordinates of S0 while optimizing the S1*. Is it right?
>>>>>
>>>>>Of course it better to start from good coordinates for excited state optimization. The best chose is ground state geometry.
>>>>>> What should I do with the "1st excited state is B3U"?
>>>>>Nothing. It is just first excited state of porphyrin.
>>>>>>This step is very important for understanding. By using the optimized coords. of S0 in optimizing S1*, do you mean that the coordinates of atoms don't change in excited state?
>>>>>No. Any geometry optimization by definition changes atomic coordinates.
>>>>>>4) You have used PCM calculations all throughout.. They don't seem time consuming. What all solvents I could use for the same? Do I have acetonitrile available?
>>>>>Did you check manual? There are two manual available. Th new one and old. Check both of them. CH3CN is available.
>>>>>
>>>>>
>>>>>>Pavlo until your help, I was in this notion that I should get the most probable orbitals from UV-Vis. calculations and then optimize them for S1 and then obtain the emission spectra. But you haven't talked about most probable orbitals anywhere... Where do I apply the concept I just mentioned then?
>>>>>Sorry, by i don't understand what you are trying to say within DFT level of theory.
>>>>>
>>>>>
>>>>>Hope this helps.
>>>>>Pavel.
>>>>>
>>>>>
>>>>>
>>>>>>Kind Regards,
>>>>>>
>>>>>>
>>>>>>
>>>>>>On Thu Jun 12 '14 10:18am, Siddheshwar Chopra wrote
>>>>>>---------------------------------------------------
>>>>>>>Dear Pavel,
>>>>>>>Your suggestions have always been valuable to me. I will start working on your files and will let you know in case I need your help.
>>>>>>>Kind Regards,
>>>>>>>On Wed Jun 11 '14 4:17pm, Pavlo Solntsev wrote
>>>>>>>----------------------------------------------
>>>>>>>>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.
>>>>>>>>Pavel.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>On Tue Jun 10 '14 10:16pm, Siddheshwar Chopra wrote
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>>>>>>>>>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
>>>>>>>>>----------------------------------------------
>>>>>>>>>>Hello,
>>>>>>>>>>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,