On Mon, Apr 24, 2017, Vatsal Purohit wrote:
>
> I am trying to run an antechamber program on a ligand pdb file and getting
> the following error:
> QMMM: Unable to achieve self consistency to the tolerances specified
> QMMM: No convergence in SCF after 1000 steps.
>
>
> I tried to generate a mol2 file with this modified ligand using antechamber
> and got that error. This method has worked for other ligands but with this
> one I've been having problems. I have tried to change the value of scfconv
> to 1.d-8, tight_p_conv to 0 and grms_tol to 0.002 and have still gotten the
> same error.
See p. 284 of the 2017 Reference Manual for hints. Basically, the only
thing I see is to try adding ndiis_attempts=700 to your sqm input file.
Alternatives: since you already have Gaussian runs, try using '-c resp' rather
than '-c bcc'. You may have to re-run the final Gaussian calcualtion with
the new iops (look at example 12 on p. 280). Or (often easier): use
the R.E.D. server to get resp charges.
All that said, highly charged phosphates are often a source of problems; of
course, that's not much solace....
...good luck....dac
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Received on Tue Apr 25 2017 - 05:30:02 PDT
