Subject: TD-DFT capacities of Gaussian 98

From: Demetrio Antonio da Silva Filho <[email-masked]>
Date: Fri, 04 May 2001 21:43:32 -0700

Der CCL'ers,

I'm posting a question that a friend asked me to because he sent it to
gaussian and he didn't get any answer so far.

Thanks,

Demetrio Filho

I am using the Gaussian version:
Gaussian 98: SGI64-G98RevA.7 11-Apr-1999
13-Apr-2001
on an SGI cluster.

  My problem is the following:
I have studied absorption processes in the singlet and triplet manifolds of
conjugated oligomers using TD-DFT. The calculations yielded excellent 
agreement
with experimental data considering the energetic positions of the transitions.
Also the transition matrix elements from the ground to the one-photon allowed
states seemd to be very reasonable. As a next step I tried to study two-photon
absotrption processes. Again, the energetic positions of the excited states
were very nicely described - to erive the absorption cross-sections I employed
a perturbative approach containing the transition matrix elements between a
number of excited states. To calculate them I used the option
alltransitiondensities with the TD keyword. In the manual this option is,
however, mentioned only in the context of HF-SCI calculations and I think I
remember that someone at a Gaussian workshop I attended some time ago, told me
that it is not possible to calculate transition matrix elemnts between excited
states using TD-DFT. The results I obtained were insofar reasonable, as only
the two photon allowed states "had" os\cillator strength, but the actual 
values
I obtained for the transition matrix elements were too large (usually by about
a factor of around 3. Do you know, wheteher this is due to transition matrix
elements between excited states being not yet "fully included" in the TD-DFT
capacities of Gaussian 98?

thank you, egbert zojer

---

From: Nguyen Kiet A Contr AFRL/MLPJ <[email-masked]>
Date: Fri, 4 May 2001 17:50:15 -0400

Here is the message from Doug Fox about transition dipoles between excited states from TDDDFT and RPA for version A.9.

 Rev. A.9 still does not include code to produce relaxed densities
for TD-DFT or RPA.  The code to loop over all transition densities
in the population analysis not available yet.  The densities are
written out but there is no current code to process them.

   You can get any selected transition density used in the population
analysis with Density=Transition=(n,m) IOP(6/22=-4) but I am not sure
what this your user wants.

    As you know the ground to excited state dipole moments are printed
and these are reasonable although not quantitative.  The transitions
between excited states have not been studied.

> ----------
> From: 	Demetrio Antonio da Silva Filho
> Sent: 	Saturday, May 5, 2001 12:43 AM
> To: 	[email-masked]
> Subject: 	CCL:TD-DFT capacities of Gaussian 98
> 
> Der CCL'ers,
> 
> conjugated oligomers using TD-DFT. The calculations yielded excellent agreement 
> the two photon allowed states "had" os\cillator strength, but the actual values