[gmx-users] fixed dihedrals

[Christoph Freudenberger]

Gerrit Groenhof wrote:
>>
>>Dear all,
>>
>>is it possible to fix single dihedral angles
>>during a MD run. If yes, what's the easiest
>>way of implementation?
> 
> 
> You can use an improper dihedral. Using a proper dihedral with a too
> strong potential might result in integration errors I think.

If the rest of the molecule is already constrained (all-angles) you might
be able to use to more constraints. for a molecule like

     -1       4-
       \     /
        2---3
       /
     -5

you can add constraints for 1-4 and 5-4 to fix the diehd.

regrads
-- 
Christoph Freudenberger
Abt. Organische Chemie I AK Siehl - Uni Ulm -Tel: ++49-731-502-2785