AMBER Archive (2008)

Subject: Re: AMBER: Charge derivation: RESP vs. antechamber

From: David A. Case (case_at_scripps.edu)
Date: Tue Apr 29 2008 - 18:40:40 CDT

On Tue, Apr 29, 2008, Catein Catherine wrote:
>
>
> I am new to Antechamber, I could like to ask if we would like to do a
> calculation for an organic compounds, after doing antechamber, i notices the
> atomic charges were assigned as I can see from the xleap editor. Do I still
> need to do the RESP calculation to recalculate the atomic charges? Which
> atomic charges should I use?

You can use the "am1-bcc" charges that antechamber calculates, *or* use
RESP charges, which are somewhat more complicated to compute.

For "simple" (single configuration, etc) antchamber can help you get RESP
charges if you have Gaussian. For more complex problems, R.E.D. can be a big
help.

There is no single correct answer to the question "which ones should I use"?
Generally, am1-bcc are used for calculations on many ligands (since they are
quick to obtain, and the process is automated), whereas RESP charges are more
suitable to looking at one or a few ligands, where you can justify the
personal and computer time required to obtain them. But other people might
give different answers here....

...dac
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