TURBOMOLE Modules > Mpgrad and Rimp2
Structure Optimization employing rijk (HF) and rimp2
Stefan:
Hello,
I want to optimize a structure employing the rijk-approximation for the HF-part as well as the rimp2 approach. Employing jobex does not work. I receive the following error message:
--- Quote ---Program dscf can not use the RI-J approximation.
Please either use the ridft program or delete the option $rij
from your control file.
--- End quote ---
I used the following command to start the calculation:
--- Quote ---nohup jobex -level mp2 -ri -c 5 -gcart 4 &
--- End quote ---
The following seems to work:
1. starting ridft
2. starting rimp2
3. starting relax
4. restart with 1.
Which flag must be used to employ the jobex script?
Regards, Sefan
uwe:
Hi,
unfortunately jobex is not able to differ the RI of RI-MP2 from the RI of RI-DFT (which is RI-J).
That is a bit unfortunate, but quite easy to circumvent:
--- Code: ---export dscf=ridft
jobex -ri -level mp2 [...]
unset dscf
--- End code ---
should work.
The unset dscf line is necessary to avoid problems with non-RI-MP2 calculations in the same shell after the job, since a usual Hartree-Fock geometry optimization would also use ridft instead of dscf otherwise.
The same trick can also be used for RI-CC2 or RI-MP2 calculations with the ricc2 program (jobex -level cc2) together with RI-JK.
Regards,
Uwe
Stefan:
Thank you.
Regards, Stefan
Arnim:
Hi,
here is a little outlook for this problem.
In the next version it will be possible to perfom RI-SCF based geometry optimizations
with the jobex-script, routinely. Using the rijk-approximation for the HF-part and the CPHF-part
in MP2 or CC2 gradient calculations. The ridft and ricc2 programs will be used and everything
can be prepared in define.
Regards,
Arnim
christof.haettig:
Hi,
the optimization 'by hand' or the trick described by Uwe are work arounds for the time being, but note:
The gradients which rimp2 and/or ricc2 compute will in that case be those for conventional (i.e. non-RI) SCF+
RI-MP2 energy and do not fit 100% to the computed total energy. Probably in most cases, this will not be
a serious problem, but you should be aware that you can't use tight convergence threshold for jobex in that
case.
Christof
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