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

David van der Spoel spoel at xray.bmc.uu.se
Tue Mar 20 22:35:49 CET 2007

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 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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