Re: amber-developers: Naming scheme for the new Amber UA force field

From: Ray Luo <>
Date: Thu, 14 Jul 2005 15:07:06 -0700

>Basically, I agree with Carlos that if should be called ff03ua if it is
>really a "counterpart" to ff03.
>Can you describe the extent to which the new ua force field is the
>"counterpart" to ff03 itself? My understanding is that:
> ff03 = ff99 + new charges for amino acids
> + a few changes in backbone torsions
1. ff99 bond and angle terms. This set of terms has been shown in the UA
paper to a deliver similar agreement to the d3lyp frequencies for a
tested system as the original ff99;
2. ff03aa charging scheme;
3. ff03aa main chain torsions;
4. side chain torsions are refitted because of the new united atom types
and of course new charges.

>Is there a similar "simple" way to describe the new ua parameters?
Do you mean the leaprc script?


Ray Luo, Ph.D.
Department of Molecular Biology and Biochemistry
University of California, Irvine, CA 92697-3900
Office: (949)824-9528         Lab: (949)824-9562
Fax: (949)824-8551          e-mail:
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Received on Wed Apr 05 2006 - 23:49:54 PDT
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