clarification on difference density with ricc2?

[AntonP]

Dear all,

I just have a question concerning the calculated difference density with ricc2. To get the spatial distributions, I am computing the densities for the ground and the first excited state with (scs) cc2. In my case, the calculations went smoothly and I have got the values on the grid. However, I am not confident with the interpretation of my results: in particularly, I am getting two files like cc2-xs1d-ur-1a-001.cao and cc2-xsdn-1a-001-total.cao. The difference densities calculated based on both types of files are very similar although they do not seem to be  identical. My question is therefore the following: what is the precise difference between xs1d and xsdn types of densities and which of them (if any) contain the contributions from the correlation/doubles? Unfortunately, I could not find this in the manual. Essentially, I need this information to explain the difference in the performance of LR-CC2 with respect to TD-DFT on my system. Which densities (files) are more informative for this purpose?

Thank you in advance for your help!

Best regards,
Anton

P. S. I am using Turbomole 6.5

[Arnim]

Hi,

xxx-ur-xxx.cao hold the unrelaxed densities, xxx-total.cao the relaxed densities. You should use the relaxed ones.

Cheers,

Arnim

[AntonP]

Hi Arnim,

all right, thank you very much for the clarification! I just have one another related question: do you know if the difference density MATRIX can be extracted, as well?

Best regards,
Anton

[Arnim]

That can be done with the pointval key.
E.g. use something like this:

$anadens
 calc my_favourite_diffden from
 1d0 gsdens
-1d0 exdens
$pointval    fmt=xyz

[AntonP]

Dear Arnim,

thank you for your reply! I did it as you described and I have got two files: my_favourite_dif.xyz and my_favourite_diffden which is a binary file. Could you please suggest how to proceed in order to see from this the elements of the difference density matrix?

Best regards,
Anton

[Arnim]

my_favourite_diff.xyz should be ASCII and holds cartesian coordinates x,y,z and f(x,y,z).