It means that the self consistent field calculation didn't converge (QM
equations are non-linear, so they have to be solved iteratively until it
achieves self consistency).
Furthermore, it says that the smallest change in energy observed occurred on
step 99 (of the 1000 steps that it tried), and that the change in the
density matrix (which is what is used to determine convergence I think) was
0.06418. The final step is right above, and as you can see the change in
the density matrix is not much less than it was 901 steps previously (which
means it is converging very very slowly, if it's converging at all).
One guess would be that you have a poor starting structure. My suggestion
would be to try and obtain a more relaxed starting structure (many molecule
builders have a built-in geometry optimizer based on an empirical force
field at least).
Hope this helps,
Jason
On Wed, Jan 5, 2011 at 7:22 PM, Andre Serobian <
serobian.a.student.unsw.edu.au> wrote:
> I reran antechamber and the sqm.out file error states:
>
> ERROR!
> QMMM: Unable to achieve self consistency to the tolerances specified
> QMMM: No convergence in SCF after 1000 steps.
> QMMM: E = -0.1772E+07 DeltaE = -0.3697E+01 DeltaP = 0.5747E-01
> QMMM: Smallest DeltaE = 0.2632E+00 DeltaP = 0.6418E-01 Step = 99
>
> What does this mean?
>
> Kind regards,
>
> Andre
>
>
>
> ----- Original Message -----
> From: "case" <case.biomaps.rutgers.edu>
> To: <amber.ambermd.org>
> Sent: Thursday, January 06, 2011 12:20 AM
> Subject: Re: [AMBER] antechamber error
>
>
> >
> > On Wed, Jan 05, 2011, Andre Serobian wrote:
> > >
> > > Running: /usr/local/amber11/bin/sqm -O -i sqm.in -o sqm.out
> > > Error: cannot run "/usr/local/amber11/bin/sqm -O -i sqm.in -o sqm.out"
> > > of bcc() in charge.c properly, exit
> >
> > You need to look at the sqm.out file for information about what went
> > wrong.
> >
> > ...dac
>
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--
Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
352-392-4032
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Received on Wed Jan 05 2011 - 21:30:04 PST
