[gmx-users] Can not find forcefield for atom C4-1 with 0 bonds

Justin A. Lemkul jalemkul at vt.edu
Mon Nov 9 14:09:53 CET 2009

Darrell Koskinen wrote:
> Hi,
> I am trying to create a topology file from a .gro file. When I run x2top 
> with methane (C4 opls_066) in my .gro file, I receive the following 
> warning:
> /Can not find forcefield for atom C4-1 with 0 bonds/
> I have included the following line in the ffoplsaa.n2t file, which 
> resides in my working directory:
> /C4   opls_066    0      16.043  0/
> I thought that the inclusion of the name to type definition for C4 in 
> the .n2t file would have resolved the above warning.
> Please let me know if there is something else I must do to resolve this 
> problem.

It appears that x2top simply does not work if there aren't any bonds.  I suppose 
that makes sense; the topology for a united-atom methane would be a single [ 
atoms ] entry, which is trivial to create by hand.


> Thanks.
> Darrell


Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080


More information about the gromacs.org_gmx-users mailing list