I want to calculate the spin orbit coupling matrix elements (SOCME) between first singlet excited state (S1) and triplet excited states (T1, T2, T3, ....). I have done the TDDFT calculation using Gaussian16 using td (50:50) command. Now, I want to determine the SOCME from the output file. Is there any program/script to do so?
Dear Kalyan J Kalita ,
I didn't know Gaussian had the possibility to perform spin-orbit coupling and I would be interested in the input you gave.
Otherwise, even though I might not give you an answer to your problem, I know ORCA output give very good output for this purpose, in the case you could be interested in using it.
Thank you Tian Lu for the insightful answer. Everything in the tutorial went well, apart from the "grid4" keyword in the input is not working for some reason in Orca 5.0. Aso can you suggest how to visualise the isosurface of excited state molecular orbitals (S1, T1, T2, T3....) etc.
Kalyan J Kalita ORCA 5.0 no longer supports "grid" keyword, the default grid in ORCA 5.0 is already good enough for nearly all cases.
TDDFT calculation doesn't generate a new set of molecular orbitals, the excited states are calculated on the top of MOs of ground state, so in principle it is impossible to visualize MOs of excited states. (To obtain MOs of excited states, you need to use the methods involving orbital optimization procedure, such as delta-SCF, MOM, and so on, but they are not popular and universal methods of calculating excited states)
Tian Lu Thank you very much for the useful comment. I have one more query regarding the equation 5 of the following PCCP paper that you mentioned in your tutorial.Article Semi-quantitative assessment of the intersystem crossing rat...
ORCA outputs SOCME in both Cartesian basis (Z, X, Y) as well as in terms of MS=(0,-1,+1). Does the equation 5 of the PCCP paper (image attached) is valid for the SOCME in terms of MS?
That paper was using ADF's pSOC-TDDFT implementation. The spin-orbit coupling matrix elements are available. These are , but for convenience we also print the averaged SOCME. See e.g. this TADF tutorial: https://www.scm.com/doc/Tutorials/OpticalPropertiesElectronicExcitations/OptimizingTADFEmission.html?highlight=SOCME
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