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Alex Granovsky
gran@classic.chem.msu.su

I'll answer you when I'll have more time. The explanation is somewhat lengthy.

Kind regards,
Alex Granovsky

On Fri Sep 26 '14 2:48pm, Siddheshwar Chopra wrote
--------------------------------------------------
>Dear Alex Sir,
>I would be really grateful if you could throw some light on the transition density matrix calculation. Is it possible to determine the matrix from TDDFT output file? IF yes then I would attach one file. Kindy let me know Sir.

>Kind Regards,
>
>
>On Sat Sep 20 '14 8:10am, Siddheshwar Chopra wrote
>--------------------------------------------------
>>Dear Pavlo Sir and Alex Sir,
>>Thank you so much for the useful information. Alex sir I am really happy to know that it is possible to find TDM from PUNCH file (from TDDFT calc.). I would request you to elaborate the process for the same. Right now I dont have any punch file with me. Can you explain with the help of any punch file? Once that is clear, I will look for the program.
>>Also, Sir I found that transition dipole moment matrix in the TDDFT o/p file is of the size NSTATE X NSTATE. Can you explain how to analyse this? I find the x,y,z data corresponding to an i,j element. Does the magnitude of this dipole moment = sqrt(x^2+y^2+z^2)? Any help would be welcomed. If I plot this graph, what could be conveyed from this?

>>Kind Regards,
>>
>>
>>On Sat Sep 20 '14 1:28am, Alex Granovsky wrote
>>----------------------------------------------
>>>Dear Siddheshwar,
>>>Dear Pavlo,

>>>internally, Firefly (and other QC codes) uses one-particle TDM to
>>>compute such properties like transition dipole moments/dipole
>>>velocities and oscillator strengths. These is no option at present
>>>to print out a computed one-particle TDM.

>>>@Siddheshwar:
>>>

>>>for TDDFT, one-particle TDM can be recovered using an information  
>>>found in the punch file. You will need to write small Fortran
>>>or C program for this.

>>>Kind regards,
>>>Alex Granovsky
>>>
>>>
>>>On Thu Sep 18 '14 8:37pm, Pavlo Solntsev wrote
>>>----------------------------------------------
>>>>ok,
>>>>
>>>>
>>>>TDM you can get for MCSCF/XMCQDPT jobs. I am not sure about DFT. By default TDM is not available in the output file. Probably, Alex may answer your question regarding DFT/TDDFT level of theory.

>>>>-Pavlo.
>>>>
>>>>
>>>>
>>>>On Thu Sep 18 '14 1:36pm, Siddheshwar Chopra wrote
>>>>--------------------------------------------------
>>>>>Dear Pavlo,
>>>>>I read an article which used the Transition density matrix analysis. According to it, transition densities represent coherent electronic transitions between ground and electronically excited states.

>>>>>Some references:
>>>>>a) S. Mukamel, S. Tretiak, T. Wagersreiter, V. Chernyak, Science1997, 277,781 – 787;
>>>>>b) S. Tretiak, K. Igumenshchev, V. Chernyak,Phys. Rev. B2005,71, 033 201;
>>>>>c) S. Tretiak, S. Mukamel, Chem. Rev.2002, 102, 3171 – 3212;
>>>>>d) S. Tretiak, V. Chernyak, S. Mukamel,Chem. Phys. Lett.1996, 259,55–61;
>>>>>e) K. I. Igumenshchev, S. Tretiak, V. Y. Chernyak,J. Chem. Phys.2007,127, 114902;
>>>>>f) Y. H. Li, C. A. Ullrich, Chem. Phys.2011, 391, 157 – 163.

>>>>>The transition-density matrix analysis helps in pointing out the section of structure/molecule from where the electronic transition mainly occurs.
>>>>>Also I found a paper which describes the relation between transition dipole moment and transition density.
>>>>>a) Mengtao Sun,Jianing Chen and Hongxing Xu, THE JOURNAL OF CHEMICAL PHYSICS 128, 064106
2008.

>>>>>In general transition density contains information about the spatial location of the excitation.

>>>>>Kind Regards,
>>>>>
>>>>>
>>>>>On Thu Sep 18 '14 5:01am, Pavlo Solntsev wrote
>>>>>----------------------------------------------
>>>>>>Dear Siddheshwar.

>>>>>>Could you please explain me what Transition density matrix stands for?

>>>>>>-Pavlo

>>>>>>On Wed Sep 17 '14 9:45am, Siddheshwar Chopra wrote
>>>>>>--------------------------------------------------
>>>>>>>Dear Users,
>>>>>>>I wish to know about the determination of Transition density matrix. How do we extract it from the o/p data? Do we need to mention any special command to get the same? If no, then how to search for it in the o/p file? What all we can infer using it? Someone please throw some light on it.

>>>>>>>Kind Regards,