AMBER Archive (2008)

Subject: Re: AMBER: question about the charge

From: Carlos Simmerling (
Date: Fri Jun 27 2008 - 15:52:22 CDT

I'm not sure I exactly understand your question, because there are several
aspects. one is that the prmtop charge units are not standard- see the
amber web site for info. Once you have converted your charges to the
appropriate units, then you could use those in the prmtop. how well
those charges work depends on what you are trying to study, and other
factors such as whether you will have charges for other parts of your system
(solvent, other solutes) that do not use the same charge model as yours.

On Fri, Jun 27, 2008 at 4:37 PM, Harry (Yicun) Ni <> wrote:
> Hello,
> I have a question about the charge of atom used in Amber. I wonder what kind
> of charge it is in the prmtop file.
> Is it the Mulliken charge or point charge used in Amber. Because we have
> already fit the Mulliken charge to
> point charge used for static electronic energy calculation for some
> molecule, whether it is OK for me to use
> our charges directly in prmtop file instead of the charges generated by
> Xleap in prmtop file. Thank you very much.
> Harry
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