Molden file for an excited state

Dear, Q-chem users

I am studying excited states, through TD-DFT formalism. I am interested in using AIMAll suite to analyze the wave function of a specific excited state. For this purpose, I have been using the molden file as printed by q-chem, but I always obtain de molden orbitals for the ground state.

Is there a way to print molden, fchk or wfn files for a specific excited state?

I thank your time

Best regards

My input file for benzene molecule

 0 1
         C         0.1766025298   -1.3831100418   -0.0000642602
         C        -1.1091486613   -0.8440392726   -0.0001325799
         C        -1.2861943091    0.5388740599   -0.0001524743
         C        -0.1765396408    1.3830970879   -0.0000775712
         C         1.1091181584    0.8440650085   -0.0000023315
         C         1.2861764727   -0.5389479950    0.0000002187
         H         0.3133148820   -2.4587719400   -0.0000464700
         H        -1.9716043687   -1.5011053407   -0.0001973857
         H        -2.2863850353    0.9573098384   -0.0001980363
         H        -0.3133962125    2.4587405110   -0.0000961451
         H         1.9716586458    1.5010201848    0.0000613166
         H         2.2864215648   -0.9572534823    0.0000436208
   BASIS  =  6-311++G(2d,2p)
   METHOD  =  t-HCTHh
   CIS_N_ROOTS   =  4
   CIS_SINGLETS  =  true
   CIS_TRIPLETS  =  true
   print_orbitals = true
   RPA = 2



   BASIS  =  6-311++G(2d,2p)
   METHOD  =  t-HCTHh
   molden_format = true
   WRITE_WFN = bn-T1
   IQMOL_FCHK = true
   CIS_N_ROOTS   =  4
   CIS_SINGLETS  =  true
   CIS_TRIPLETS  =  true

There is a way. Listed below is a sample job from the manual. The Molden-formatted files (one per state, since the NTO are state-specific) are deposited in a sub-directory called “NTOs” in the job’s scratch directory, which means that you need to be sure to save the scratch files. Run Q-Chem with a command that is something like

qchem -save output.out scratchname

and then find the $QCSCRATCH/scratchname/NTOs. There are files called, e.g., TDA.singlet.1 (first singlet state for the Tamm-Dancoff calculation, could also be RPA instead of TDA if you ran both calculations). Next state is TDA.singlet.2, etc.

uracil excited states; generate NTOs

0 1
N -2.181263 0.068208 0.000000
C -2.927088 -1.059037 0.000000
N -4.320029 -0.911094 0.000000
C -4.926706 0.301204 0.000000
C -4.185901 1.435062 0.000000
C -2.754591 1.274555 0.000000
N -1.954845 2.338369 0.000000
H -0.923072 2.224557 0.000000
H -2.343008 3.268581 0.000000
H -4.649401 2.414197 0.000000
H -6.012020 0.301371 0.000000
H -4.855603 -1.768832 0.000000
O -2.458932 -2.200499 0.000000

BASIS 6-31+G*

Jherbert, Thank you for your valuable response,

I tried to analyze the TDA.x.n and RPA.x.n files but they are not useful for me, because they are not counting all the electrons and orbitals for construct a wave function of the excited state.

With this in mind, I was able to obtain the Natural Orbitals, e.g.,, printed in the $plots directory. These orbitals are completed but I faced another issue: when I convert these molden files to a .wfx file using molden2aim, the code shows me

Warning: the total electron is different from the sum of occupations!
#Electron = 42.0000
Sum_Occupation = 20.0000
#Core Electron = 0.0000
Net Charge = 22.0000
For the benzene molecule.

Reviewing the molden file printed by qchem I find, besides that beta MOs of R-/RO-SCF are not printed, the occupations number is also incorrect.

Lastly, I edited the *.mo files to adjust the occupation numbers, I just change Occup=0 to Occup=1 in the next empty orbital.
With this edited file, I proceed to convert it to .wfx and integrate the wave function file in AIMALL but I obtain the same atomic properties for the Ground State and Excited states wave functions, so there is something wrong in the .mo files.

Do you know a way to print the complete molecular orbitals for specific excited states?
Is this error common in molden files printed by q-chem?

P.S. I also tried Unrestricted calcs but no luck.

Best regards

I am not 100% sure that I understand your question. Typically we use the NTOs just for visualization purposes. The number of them that is printed is controlled via NTO_PAIRS. For the occupancies, check whether you are off by a square root. Eigenvalues of the difference density matrix (Delta P) are the squares of the singular values of X (TDA) or X+Y (RPA).

I am not familiar with AIMALL.


I am sorry, the problem is simple: the orbitals printed in are the same as GS orbitals, not of the T1 Excited State.

And also the occupation of these orbitals saved in $plots is incorrect, now I know that is a bug in q-chem.

molden2aim output:

** WARNING ***
  There is a BUG in Q-Chem RO-SCF. In this case, 
  please correct the  occupation numbers of singly occupied MOs manually.

Well, do you know a way to fix my any of these problems?

Thank you!

Short answer to 2nd problem is ‘no’. I’m not familiar with ‘molden2aim’ (at all) so I don’t know how to help with that. For the first part, I’ve been trying (failing) to find some time to look into this, but it seems like you may have found a bug. The best way to get it looked into is to submit a bug report to Q-Chem support (see here for contact info: Describe the problem and send a sample input/output that illustrates it. They will create a ticket and someone (maybe me) will try to look into it.
Thanks in advance. -John