On Thu, May 08, 2014, hannes.loeffler.stfc.ac.uk wrote:
>
> So, the following name list does converge the structure.
>
> &qmmm
> qm_theory='AM1',grms_tol=0.0002,tight_p_conv=0,
> scfconv=1.0d-9,itrmax=500,pseudo_diag=1,vshift=0.1,
> ndiis_attempts=200,ndiis_matrices=6,maxcyc=2000,
> qmcharge=-1,verbosity=1
> /
Thanks for the info: we should probably be suggesting use of vshift more
prominently in the case of convergence problems.
>
> Except that the structure gets "folded" (see attachment) with the
> carboxy groups contacting the amino groups.
I suspect that these odd geometries are related to convergence problems.
Your initial geometry converged fine, but after some steps of minimization,
which probably involved some "folding", you ran into problems.
...regards...dac
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Received on Fri May 09 2014 - 13:00:02 PDT
