Stephane,
If you want a good agreement between the charges you are testing & the
dihedral for your solvent box I would follow what Ilyas Yildirim
suggested (his paper is a pretty good example).
regards, Francois
Quoting Stephane Abel <Stephane.Abel.cea.fr>:
> Dear AMBER users,
>
>
> I am trying to build the trifluoroethanol parameters from GAFF force
> field for MD with GROMACS code. For this purpose the parameters in the
> GAFF.dat file given in the ambertools package (v. 1.4). I have defined
> the TFE atome types as follows :
>
>
> [ TFE]
> [ atoms ]
> C1 C3 0.64900 1 <---- C3 is as a Sp3 C
> (correct ?)
> C2 C3 0.09760 2
> O1 OH -0.57850 3
> F11 F -0.23790 4
> F12 F -0.23790 5
> F13 F -0.23790 6
> H21 HC 0.06200 7
> H22 HC 0.06200 8
> H3 HO 0.42150 9
> [ bonds ]
> C1 C2
> C1 F11
> C1 F12
> C1 F13
> C2 O1
> C2 H21
> C2 H22
> O1 H3
>
>
> I can define all the bond and angle parameters. But for dihedral
> parameters, the OH C3 C3 F quadruplet is not present in the
> gaff.dat file.
>
> Any advice is welcome
>
> Stephane
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Received on Fri Jan 21 2011 - 23:00:06 PST
