Dear Sudeb Ghosh ,

Assuming that you are using Gaussian, the program does not perform the population analysis (and thus does not calculate the dipole moment) for excited states unless it is explicitly requested. And even that, it does it for a single state at once, as far as I know.

For instance, let's assume that you are interested, for whatever reason, in the seventh excited state from your calculation. Then, to get the population analysis (and the dipole moment) for that state, the keyword route should be:

b3lyp/tzvp td=(nstates=10,root=7) density=current

With those new keywords you are telling the program to do the population analysis in the state you want. And in the output you will get all the information for that state. Without those keywords, you get the population analysis for the ground state by default.

Hope you find it helpful

Dear Enrique Manuel Arpa ,

Thanks for your generous help. I understood what you have said in your reply. I just have a query regarding my TDDFT output file. I have found in my file, "ground to excited state transition electric dipole moments", which is attached below. Can I get dipole moments from this file? Please look at the file below.

1PDM for each excited state written to RWF 633

Ground to excited state transition densities written to RWF 633

Ground to excited state transition electric dipole moments (Au):

state X Y Z Dip. S. Osc.

1 1.7083 -0.5791 0.0000 3.2538 0.2338

2 -0.0006 -0.0002 -0.0993 0.0099 0.0008

3 -1.7231 -0.0777 0.0001 2.9750 0.2602

4 -0.0006 0.0001 0.0062 0.0000 0.0000

5 -0.0001 0.0000 0.0058 0.0000 0.0000

6 -0.1371 0.2688 0.0000 0.0910 0.0096

7 -0.6207 0.0317 0.0000 0.3863 0.0429

8 0.0001 0.0001 -0.0614 0.0038 0.0004

9 -2.4579 -0.8830 0.0000 6.8208 0.8033

10 0.7974 -0.2813 0.0000 0.7149 0.0897

11 -0.0003 -0.0001 0.0497 0.0025 0.0003

12 0.0000 0.0001 -0.0157 0.0002 0.0000

13 -1.9437 0.3990 0.0000 3.9372 0.5460

14 -0.5924 0.2406 0.0000 0.4088 0.0591

15 -0.0002 0.0001 -0.0018 0.0000 0.0000

16 -0.0001 -0.0001 0.0600 0.0036 0.0005

17 0.0444 0.1511 0.0000 0.0248 0.0037

18 -0.0007 -0.0009 0.0055 0.0000 0.0000

19 -0.3869 -0.5501 0.0000 0.4523 0.0684

20 0.5983 0.4331 0.0000 0.5455 0.0835

21 -0.0002 -0.0001 -0.0363 0.0013 0.0002

22 -0.0004 0.0010 -0.0346 0.0012 0.0002

23 -0.0745 0.6488 0.0000 0.4265 0.0673

24 0.0095 0.4332 0.0001 0.1878 0.0298

25 -0.0002 0.0001 -0.0560 0.0031 0.0005

26 -0.3180 0.2744 -0.0002 0.1764 0.0287

27 0.0001 -0.0008 -0.0431 0.0019 0.0003

28 0.0006 0.0011 -0.2261 0.0511 0.0084

29 -0.0003 -0.0004 0.0217 0.0005 0.0001

30 -0.1649 -0.9722 -0.0003 0.9724 0.1629

Ground to excited state transition velocity dipole moments (Au):

state X Y Z Dip. S. Osc.

1 -0.1740 0.0708 0.0000 0.0353 0.2183

2 0.0001 0.0000 0.0198 0.0004 0.0021

3 0.2200 0.0126 0.0000 0.0485 0.2467

4 0.0001 0.0000 -0.0007 0.0000 0.0000

Sudeb Ghosh ,

The transition dipole moment is not associated to just the ground or the excited state, but, as the name says, to the transition from one to the other. In few words, it measures the interaction between the initial and final electronic states.

So, as far as I know, you cannot get the dipole moments for the excited states from that piece of information.

Dear Enrique Manuel Arpa,

I am still getting the ground state dipole moment even after using density=current keyword. Please help me to sort it out. I have attached my TDDFT input and output file.

Sudeb Ghosh ,

If you take a closer look to the output file, it never got to start the last calculation (the one in which you requested the excited state density). That is because you wrote Link2 instead of Link1. You don't have to increase the number, Link1 is the Gaussian module that initializes a calculation, so when you write it in an input you are calling it so a new, consecutive calculation can start.

Change the Link2 by Link1 and it should work. Or even better, if you still have the checkpoint file, just remove everything before the Link2 line (including that one, so your first line is the one where you define the chk file) and submit that calculation. Don't forget to include a blank line at the end of the input, it seems it is missing right now (the last one now is the 0 1)

Let me know if this works now

@Enrique Manuel Arpa,

Thanks a lot for your help.