On Thu, Jul 11, 2019, Thomas Evangelidis wrote:
>
>Maybe this is a recurrent question. I know there are better methods to
>optimize ligand geometry than AM1. For instance, I am using PM6. However,
>for the charge calculations, is the AM1 method with bcc corrections the
>recommended one? Can I replace it with the more rigorous PM6 or those
>charges would not be compatible with the GAFF2 force field?
The charge corrections applied in AM1-BCC assume that one is starting
with AM1 charges. As noted before, the initial derivation of these used
AM1-optimized geometries as well.
You are welcome to use a PM6-optimized geometry: just tell antechamber not
to minimize the input structure when computing AM1-BCC charges. I don't
think it is likely to generally be good to replace AM1 charges with PM6
charges, since the bond correction terms are designed to (partially) fix
the deficiencies of AM1 charges.
....dac
_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Thu Jul 11 2019 - 07:00:02 PDT
