[gmx-users] How to extend Ryckaert-Bellemans parameters?

[David van der Spoel]

Nicolas Sapay wrote:
> Hello everybody,
> 
> I need to extend Ryckaert-Bellemans parameters to C6 in order to take 
> into account dihedrals in alkyl chains. What parts of the source code 
> need to be modified exactly? I'm sure it is pretty trivial to do that, 
> but I can't find by myself the functions and/or structures involved in 
> the R-B potential calculation. Can someone help me? I have already a 
> .itp file with the correct number of parameters.
> 
> Nicolas
> 
> ps: I have read the previous posts on the topic... Unfortunately, the 
> parts of the code to modify were not indicated.
> 
You can actually do it simpler. By adding a proper dihedral with 
multiplicity 6 in the top file. You then have two dihedral functions on 
one bond.

-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se
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