Re: [AMBER] Forcefield_PTM

From: David A Case <>
Date: Tue, 21 Oct 2014 10:47:22 -0400

On Tue, Oct 21, 2014, Jason Swails wrote:
> The other two families have, as far as I know, only 1 member each. The
> ff03 family still uses RESP to derive charges, but uses B3LYP/cc-pVTZ
> rather than HF/6-31G* to derive charges. This DFT method accounts for
> exchange and correlation, and so yields less-polarized charges than the
> original Merz-Kollman approach.

Just a couple small additions here: ff03 also uses PCM in its charge model
(albeit with a fairly low extenal dielectric). Also, there is an "r1"
(revision 1) modification to the original force field, and it is strongly
recommended that you use that (i.e. use leaprc.ff03.r1) for calculations
involving ff03. (Cf. Section 3.4 of the Amber14 Reference Manual).


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Received on Tue Oct 21 2014 - 08:00:03 PDT
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