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31
I am interested in studying a 2 electron system, therefore CCSD stands as very useful "basis set exact" energies for me.

I would like to compare the electron densities from other methods to a reference accurate electron density. I am hoping CCSD can provide electron densities as well.

So far I have tried using the "proper" program to generate plots of the electron density along the z axis. This works well for HF and DFT calculations, but when I run the same for CCSD I appear to get the density for the reference Slater determinant, rather than a correlated density. This is apparent as comparing the HF reference density and the CCSD density show they are exactly the same.

I would like to ask if it is possible to plot the correlated density from the CCSD solution?

I admit my knowledge of coupled cluster methods is not well developed, so maybe what I am asking is not meaningful. It seems to me that CCSD solves to find a correlated wavefunction as a combination of the reference ground state with weighted excitations, I would like to plot the electron density of that correlated wavefunction, if possible.

Any advice around this is appreciated.

EDIT:
It occurs to me this might not be the correct place to ask this. Please move the post if it is in the wrong section.
32
Define / Re: how to incorporate higher symmetry point groups?
« Last post by uwe on October 06, 2020, 06:56:33 PM »
Hello,

it is not possible to use C_infinity (for a linear molecule, I guess), C99 is the maximum one can set. But you have a finite number of orbitals, so to obtain exact degeneracies a point group which covers the number of orbitals within one irrep should be sufficient, I guess.
Regards
33
Mpgrad and Rimp2 / Re: jobbsse with rimp2
« Last post by Arnim on October 01, 2020, 03:31:19 PM »
If you have set up the $ricc2 keywords correctly, you can just call 'jobbsse -ricc2'.

Cheers,
Arnim
34
Hello Roger,

in short: 't2x' converts the coordinates from the gradient file, 't2x -c' the coordinates from the coord file.

The reason that this differs is because the optimiser (statpt by default) checks whether the convergence criteria are meet and then writes out one last geometry. In order to have orbitals that match these coordinates, one last SCF run is done.

If you run 'sdg energy' and 'grep cy gradient', you will notice that there is one last energy for which is no gradient. This is the energy that belongs to the coordinates in the coord file.

If you need the most right energy (say for a reaction calculation), use the one from 't2x -c'.

I hope that clear this up.

Arnim
35
Aoforce and Numforce / Re: Aoforce restart?
« Last post by agnesst on October 01, 2020, 03:14:47 PM »
Thank you, Uwe!
36
Riper / Sublimation enthalpy & entropy of salt
« Last post by Glxblt76 on September 30, 2020, 09:34:35 AM »
Dear Turbomole developers and users,

I'm thrilled to see that now lattice parameters can be optimized using Turbomole. This means that ab initio screening of sublimation enthalpies becomes at least something technically feasible (setting aside the challenge to achieve experimental accuracy).

My questions here are twofold:
1 - do you see any route to predict the entropy of sublimation from riper outputs?

2 - Regarding organic salts, do we need to provide a neutral complex as initial guess or is it possible in any ways to leave the task of initial positionning of cation(s) and anion(s) in the unit cell?

Best regards.
37
Define / how to incorporate higher symmetry point groups?
« Last post by saparya on September 30, 2020, 05:02:41 AM »
how to incorporate higher symmetry point groups like 'Cinfinity,v' and 'Dinfinity,h' in 'define' for obtaining exact degeneracies in the molecular orbitals?
38
Hey guys!

I came upon a puzzling "feature" of the t2x script. See below my results of t2x -c and the last entry of t2x:

t2x:

6
 Energy =    -475.2662961282
 F    1.3809469   -1.0945653   -0.0000000  0.00   -0.0011503    0.0012745    0.0000000
 C    0.6600148    0.0000000    0.0000000  0.00    0.0018920    0.0000000   -0.0000001
 F    1.3809469    1.0945653   -0.0000000  0.00   -0.0011503   -0.0012745    0.0000000
 C   -0.6600148   -0.0000000   -0.0000000  0.00   -0.0018920    0.0000000    0.0000001
 F   -1.3809469   -1.0945653    0.0000000  0.00    0.0011503    0.0012745   -0.0000000
 F   -1.3809469    1.0945653    0.0000000  0.00    0.0011503   -0.0012745   -0.0000000

t2x -c:

6
Energy = -475.2662962055
F     1.3808817   -1.0945270    0.0000000
C     0.6600139    0.0000000   -0.0000000
F     1.3808817    1.0945270    0.0000000
C    -0.6600139   -0.0000000    0.0000000
F    -1.3808817   -1.0945270   -0.0000000
F    -1.3808817    1.0945270    0.0000000

You will see differences in the coordinates and the energies. These are quite small and especially for the coordinates presumably negligible. But my questions are: Where does this difference come from and which results are the "more right" ones? I might add, that I use turbomole version 7.1. I very much thank you in advance!

Best regards
Roger
39
Aoforce and Numforce / Re: Aoforce restart?
« Last post by uwe on September 26, 2020, 12:31:56 PM »
Hello,

aoforce does a restart by default. There are a couple of checkpoints where the restart data is saved to disk, and the last complete checkpoint is used automatically. There should be a keyword $restart force in the control file, and if a new start of aoforce find this keyword, it will read in all available intermediate results.

If the calculation takes very long, check if the amount of memory ($maxcor) is sufficient. In the output of aoforce, there is a section:

 Blocking parameters
 shells:
    index      start shell   last shell  start bf    last bf    #bf
       1             1          90             1        252    252
etc.

If there is more than one line, aoforce cannot use a sufficient amount of memory to do the whole job in one sweep, and it divides the tasks into individual blocks. The more blocks (lines) you have, the longer the job will take - but it will finish sooner or later and not stop due to insufficient memory.

The hopefully good news is that for large systems the generation of dS, g_sxi_a, etc. is the most time consuming step and the subsequent CPKS iterations will not take as much time.

Good luck!

40
Aoforce and Numforce / Aoforce restart?
« Last post by agnesst on September 25, 2020, 02:27:56 PM »
Hi,

Is there a possibility to restart aoforce calculation? (I use TM 7.4)
If I already have generated the large files dS, dF, g_sxi_a, rhs_a, sxi_a, etc.? (Which takes ages to generate them for big system...)
Not to have to start from the beginning?

I would be grateful for answer and help.
Thanks!
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