Hi Dan,
I noticed your QM region includes two far apart (~10 Angstrom) molecules
(chloromethane and acetonitrile). This, from my experience, may cause
problems sometime (I haven't investigated much about this issue; other QM
developers may know more). Is there particular reason for you to do this?
Otherwise, if you include chloromethane only, there should not be any
problem, at least in my test run.
Best,
Qiantao
On Wed, Jul 25, 2012 at 2:31 PM, <DJH71.pitt.edu> wrote:
> Hi all,
>
> I was having problems running PM6 on a system that contained chlorine
> atoms. I decided to experiment with a much simpler system: methane v.
> chloromethane. My original system was solvated in acetonitrile and water,
> so for consistency I solvated the methane and chloromethane as well. After
> taking the same steps to equilibrate the solvated methane and
> chloromethane, when methane was treated quantum mechanically with PM6, the
> simulations ran without problems. When chloromethane was treated with QM,
> the simulations immediately gave SCF convergence errors. I suspect it's an
> issue with the d-orbital parameters, but that is speculation. A more
> conclusive test might be to try fluoromethane as well.
>
> I've attached all input, output, prmtop and restart files for the two step
> equilibration as well as the input and output files for the QM dynamics.
> The files are in a tar-ed folder 'chloromethane.tar.gz'.
>
> It's entirely possible that this error is due to a fault on my part, but I
> thought it was worth pointing out for investigation
>
> Dan Hatfield
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Received on Fri Jul 27 2012 - 11:00:04 PDT
