[gmx-users] Multiple dihedral types in .rtp file

[Chris O'Brien]

Hello all,

I am trying to model a polymer using GROMACS.  Because it uses a 
non-standard residue, I am adding one (actually 5) to the ffgmx.rtp 
file.  I would like to use both a Ryckaert-Bellemans and a periodic 
function to best describe the dihedral rotation barriers.  What format do I 
need to use to get this to work?  Can I just use two [ bondedtypes ] lines 
at the beginning of the file that will only differ in the dihedrals 
column?  Can I define bondedtypes specifically for each residue?  However 
it is done, I want to make sure it won't interfere with the built-in 
residues in the file because others will be using GROMACS here as well.

Thank you,
Chris

Christoper O'Brien
Dept. of Chemical Engineering
Clemson University
Clemson, SC  U.S.A.