Dear colleagues,
I am new in the OLED field and just make some research about the field. Therefore I have some questions I want to confirm. I want to investigate the absorption and emission of molecule A.
1) To get the vertical absorption energy, first optimize the molecule at the ground state energy using
# td(nstates=10) opt
From the ground state geometry, perform a single point for first singlet excited state as #td(singlet,root=1,nstates=10)
The difference in the energy is vertical absorption energy. Is it correct?
I wonder if it can produce similar result to optimize molecule at dft and then perform simple td-dft of the ground state since the process also provides energy transition to first excited state?
2) for phosphoresence emission from first triplet excited state, first perform opt geometry as #td(triplet,root=1,nstates=10) opt. From the opt geometry of triplet excited state, perform #td(nstates=10) at ground state. The difference of energy is phosphoresence energy? Is it correct?
The same can be calculated for flouresence.
Thank you very much,
Sincrely,
Hi,
1) "# td(nstates=10) opt" means optimizing the lowest excited state, evidently this is not what you need.
Assume that the ground state is neutral singlet, to calculate vertical absorption energy under gas phase, firstly use for example "# PBE1PBE/6-31G* opt" with "0 1" to optimize ground state, then based on the resulting geometry, use for example "# PBE1PBE/6-31G* TD(nstates=10)" with "0 1" to carry out TDDFT calculation, then you can directly read vertical absorption energies from the output file.
2) I strongly suggest you use delta-SCF method to optimize T1 geometry, namely use for example "# PBE1PBE/6-31G* opt" with "0 3". This way is much more efficient than the TDDFT way (i.e. # td(triplet,root=1,nstates=10) opt).
Based on the optimized T1 geometry, simply use for example "# PBE1PBE/6-31G* TD(triplet)", then from the output file you will find transition energy between S0-T1, which corresponds to phosphoresence emission energy. (Alternatively, you can do single point calculation respectively with "0 3" and "0 1" then get their difference energy, it corresponds to phosphoresence emission energy computed under delta-SCF method)
Best wishes,
Tian Lu
Hi,
1) "# td(nstates=10) opt" means optimizing the lowest excited state, evidently this is not what you need.
Assume that the ground state is neutral singlet, to calculate vertical absorption energy under gas phase, firstly use for example "# PBE1PBE/6-31G* opt" with "0 1" to optimize ground state, then based on the resulting geometry, use for example "# PBE1PBE/6-31G* TD(nstates=10)" with "0 1" to carry out TDDFT calculation, then you can directly read vertical absorption energies from the output file.
2) I strongly suggest you use delta-SCF method to optimize T1 geometry, namely use for example "# PBE1PBE/6-31G* opt" with "0 3". This way is much more efficient than the TDDFT way (i.e. # td(triplet,root=1,nstates=10) opt).
Based on the optimized T1 geometry, simply use for example "# PBE1PBE/6-31G* TD(triplet)", then from the output file you will find transition energy between S0-T1, which corresponds to phosphoresence emission energy. (Alternatively, you can do single point calculation respectively with "0 3" and "0 1" then get their difference energy, it corresponds to phosphoresence emission energy computed under delta-SCF method)
Best wishes,
Tian Lu
Hi Tian,
Thank you for your reply. In delta-SCF, first I can opt the structure with "0 3" for T1 and then from the opt structure, I calculate single point with "0 1" for S0. The difference in energy is the phosphorescent energy. Is it correct?
- Also "Based on the optimized T1 geometry, simply use for example "# PBE1PBE/6-31G* TD(triplet)"..However I wonder it is " with "0 1" instead? And then we will get the transition energy from S0 to T1... right?
Thank you very much
Article ChemInform Abstract: The Calculations of Excited-State Prope...
Adsorption spectra are easy. You do exactly how you wrote. To calculate emission spectra use this tutorial
https://docs.google.com/document/d/1f2LbJMfcudxNjUrrchj8_UEKW8HLDPczRiS2m_2QbzA/pub
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