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How to interpret orbital transition in TDDFT?
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Lindsay Davis
How to interpret orbital transition in TDDFT?
Form this output you dont.
Find this in the output:
EXCITATION DE-EXCITATION
OCC VIR AMPLITUDE AMPLITUDE
I A X(I->A) Y(A->I)
--- --- -------- --------
10 17 -0.039945 0.001926
16 17 0.996619 -0.032612
16 20 -0.070681 0.003443
it shows you the involved orbitals in the transitions. This a dominant transition from the 16ths orbital to the 17ths (HOMO to LUMO). You need to visualize the MOs and decide on the nature (sigma,pi,n) of the orbitals. Since they are MOs, it can be difficult with large molecules. You can look up natural transition orbitals that aim to simplify the visualization.
How you can look at orbitals with gamess? I have no clue.
EXCITATION DE-EXCITATION OCC VIR AMPLITUDE AMPLITUDE I A X(I->A) Y(A->I) --- --- -------- -------- 10 17 -0.039945 0.001926 16 17 0.996619 -0.032612 16 20 -0.070681 0.003443
it shows you the involved orbitals in the transitions. This a dominant transition from the 16ths orbital to the 17ths (HOMO to LUMO). You need to visualize the MOs and decide on the nature (sigma,pi,n) of the orbitals. Since they are MOs, it can be difficult with large molecules. You can look up natural transition orbitals that aim to simplify the visualization.
How you can look at orbitals with gamess? I have no clue.
@user1945827 the section i gave is printed for every transition (1 to 9). OPs table is the summary at then end of the td-dft output. It becomes clear if you download the output file from OPs post.More
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To visualise the orbitals of your calculation, use a program of your choice. For Gamess, there are a few options availabile. I use ChemCraft and Molden, and they work quite well. Here is a compilation of some with the former mentioned:
You can further use the summary to identify the most interesting, strongest transitions:
SUMMARY OF TDDFT RESULTS
STATE ENERGY EXCITATION TRANSITION DIPOLE, A.U. OSCILLATOR
HARTREE EV X Y Z STRENGTH
0 A -193.0290234748 0.000
1 A -192.8724089055 4.262 0.0001 0.0000 0.0001 0.000
2 A -192.7831335626 6.691 0.4051 -0.0004 0.0000 0.027
3 A -192.7317175333 8.090 0.0018 -0.0976 0.0001 0.002
4 A -192.7220472153 8.353 -0.4522 -0.0001 0.0000 0.042
5 A -192.7210047911 8.382 -0.0121 0.0000 -0.0006 0.000
6 A -192.7176816741 8.472 -0.0001 -0.0013 0.0724 0.001
7 A -192.7167365427 8.498 0.0006 -0.0002 0.0075 0.000
8 A -192.6964881601 9.049 0.0029 -0.3152 0.0008 0.022
9 A -192.6862850361 9.326 -0.0022 1.1274 -0.0093 0.290
For the calculated 9 states that is the last one, with an oscillator strength of 0.290. Now skip back one section to where you find:
-------------------
SINGLET EXCITATIONS
-------------------
There you find the orbital transitions. You can also have a look at the amplitudes to identify the most dominant one. In this case it is probably 15 to 17 and therefore corresponds to $\pi\to\pi^*$.
The more complicated the molecules get, the more confusing will this process be. Also the higher the level of theory, the more transitions you will need to consider. In this case Natural Transition Orbitals will certainly become very helpful, see Richard L. Martin, J. Chem. Phys., 2003, 118, 4775-4777.
To visualise the orbitals of your calculation, use a program of your choice. For Gamess, there are a few options availabile. I use ChemCraft and Molden, and they work quite well. Here is a compilation of some with the former mentioned:
You can further use the summary to identify the most interesting, strongest transitions:
SUMMARY OF TDDFT RESULTS STATE ENERGY EXCITATION TRANSITION DIPOLE, A.U. OSCILLATOR HARTREE EV X Y Z STRENGTH 0 A -193.0290234748 0.000 1 A -192.8724089055 4.262 0.0001 0.0000 0.0001 0.000 2 A -192.7831335626 6.691 0.4051 -0.0004 0.0000 0.027 3 A -192.7317175333 8.090 0.0018 -0.0976 0.0001 0.002 4 A -192.7220472153 8.353 -0.4522 -0.0001 0.0000 0.042 5 A -192.7210047911 8.382 -0.0121 0.0000 -0.0006 0.000 6 A -192.7176816741 8.472 -0.0001 -0.0013 0.0724 0.001 7 A -192.7167365427 8.498 0.0006 -0.0002 0.0075 0.000 8 A -192.6964881601 9.049 0.0029 -0.3152 0.0008 0.022 9 A -192.6862850361 9.326 -0.0022 1.1274 -0.0093 0.290
For the calculated 9 states that is the last one, with an oscillator strength of 0.290. Now skip back one section to where you find:
------------------- SINGLET EXCITATIONS -------------------
There you find the orbital transitions. You can also have a look at the amplitudes to identify the most dominant one. In this case it is probably 15 to 17 and therefore corresponds to $\pi\to\pi^*$.
The more complicated the molecules get, the more confusing will this process be. Also the higher the level of theory, the more transitions you will need to consider. In this case Natural Transition Orbitals will certainly become very helpful, see Richard L. Martin, J. Chem. Phys., 2003, 118, 4775-4777.
Form this output you dont.
Find this in the output:
it shows you the involved orbitals in the transitions. This a dominant transition from the 16ths orbital to the 17ths (HOMO to LUMO). You need to visualize the MOs and decide on the nature (sigma,pi,n) of the orbitals. Since they are MOs, it can be difficult with large molecules. You can look up natural transition orbitals that aim to simplify the visualization.
How you can look at orbitals with gamess? I have no clue.
Form this output you dont.
Find this in the output:
it shows you the involved orbitals in the transitions. This a dominant transition from the 16ths orbital to the 17ths (HOMO to LUMO). You need to visualize the MOs and decide on the nature (sigma,pi,n) of the orbitals. Since they are MOs, it can be difficult with large molecules. You can look up natural transition orbitals that aim to simplify the visualization.
How you can look at orbitals with gamess? I have no clue.
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To visualise the orbitals of your calculation, use a program of your choice. For Gamess, there are a few options availabile. I use ChemCraft and Molden, and they work quite well. Here is a compilation of some with the former mentioned:
You can further use the summary to identify the most interesting, strongest transitions:
For the calculated 9 states that is the last one, with an oscillator strength of 0.290. Now skip back one section to where you find:
Look for excited state number 9:
There you find the orbital transitions. You can also have a look at the amplitudes to identify the most dominant one. In this case it is probably 15 to 17 and therefore corresponds to $\pi\to\pi^*$.
The more complicated the molecules get, the more confusing will this process be. Also the higher the level of theory, the more transitions you will need to consider. In this case Natural Transition Orbitals will certainly become very helpful, see Richard L. Martin, J. Chem. Phys., 2003, 118, 4775-4777.
To visualise the orbitals of your calculation, use a program of your choice. For Gamess, there are a few options availabile. I use ChemCraft and Molden, and they work quite well. Here is a compilation of some with the former mentioned:
You can further use the summary to identify the most interesting, strongest transitions:
For the calculated 9 states that is the last one, with an oscillator strength of 0.290. Now skip back one section to where you find:
Look for excited state number 9:
There you find the orbital transitions. You can also have a look at the amplitudes to identify the most dominant one. In this case it is probably 15 to 17 and therefore corresponds to $\pi\to\pi^*$.
The more complicated the molecules get, the more confusing will this process be. Also the higher the level of theory, the more transitions you will need to consider. In this case Natural Transition Orbitals will certainly become very helpful, see Richard L. Martin, J. Chem. Phys., 2003, 118, 4775-4777.
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