Hi everyone,
I'm performing DFT Calculation / Geometry Optimization of some 5,7-dibromobenzofurane hydrazide derivatives using ORCA 4.2.1 and BY3LP basis set (! B3LYP RIJK def2-TZVP def2/JK).
Each of 5,7-dibromobenzofurane derivatives has two isomers: anti-isomer and syn-isomer.
While the anti-isomer of a compound was successfully calculated with SCF converged after 43 cycles, the syn- one was not able to obtain the final results with this error:
----------------------------------------------------------------------------------
FINAL SINGLE POINT ENERGY -6213.007766579487 (Wavefunction not fully converged!)
----------------------------------------------------------------------------------
ERROR
This wavefunction IS NOT FULLY CONVERGED!
You can't use it for properties or numerical calculations !
Aborting the run ...
Please restart calculation (with larger maxiter/different convergence flags)
----------------------------------------------------------------------------------
Herein I attached two ouput files corresponding two isomers of a compound.
Hi Nam Q. H. Doan ,
several things could have gone wrong.
First the input structure could be of bad quality and the higher level methods fail to converge. If this is the case, try to pre-optimise the structuren using HF-3c, PBEh-3c or some cheap. And then perform the Single Point or geometry optimisation.
If the geometry is resonable, try to switch to
!KDIIS
or use a different guess, like from a cheaper DFT/HF calculation (with smaller basis set).
Just increase the number of scf cycles allowed (as suggested in the output file), However, blind increase of the steps may just be a waste of time in some cases.
Try orca 5.0 with a new SCF solver.
And have a look at:
https://sites.google.com/site/orcainputlibrary/scf-convergence-issues
Kind regards and good luck,
Conrad
The 5,7-dibromobenzofuran is meta substituted, and the entire structure is flat... How are there anti- and syn- configurations? (https://pubchem.ncbi.nlm.nih.gov/compound/5_7-Dibromobenzofuran#section=3D-Conformer)
In general: syn isomer opts may fail due to an over estimate of hinderance; so, I would have recommended a different dihedral. Of course, that will not work here.
Best, Amy
Hi,
This answer is purely technical, as I do not know much about your molecule.
You are not performing a geometry optimization. The input file is for a single point calculation.
You need TightOpt or Opt in your keywords.
Also try the RIJCOSX method instead of RIJK (Reasons are mentioned in the ORCA manual)
The B3LYP has its own problems (difficulty in convergence being the most prominent one).
I would also change the %maxcore to a reasonably high value.
I believe you can also check the GRID options given in the manual.
Please note that GRID options are different in ORCA 4 and ORCA 5
On that note:
For optimization I would use the following
! B3LYP def2-TZVP RIJCOSX def2/J TightOPT KDIIS
If this does not work try
=============================================
! BP86 def2-TZVP RIJCOSX def2/J TightOPT KDIIS
I would then perform a Single Point calculation for the geometry obtained from the above method.
For single point replace BP86 with B3LYP or any other fucntional that is suitable for your system, and remove the TightOPT keyword.
=============================================
You should also add dispersion related keyword to account for dispersion corrections.
In that case I would use
! B3LYP def2-TZVP RIJCOSX def2/J TightOPT KDIIS D3BJ
or
! BP86 def2-TZVP RIJCOSX def2/J TightOPT KDIIS D3BJ
Hope this helps.
Good luck,
Sachin
I am presently struggling with how to determine the right parameters for the modeling of ethylene epoxidation on Al2O3/Ag surface using dmol3 in materilas studio
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