[gmx-users] error running gromacs usinh charmm force field

Mark Abraham Mark.Abraham at anu.edu.au
Thu Jan 17 13:48:18 CET 2008

sarbani chattopadhyay wrote:
>   hi,
>     I am trying to run gromacs using charmm force field.
>     I run the perl program convert_charmm_to_gromacs.pl on the charmm 
> force field input
> file.
> the following 2 files were generated
>                                                       ffcharmmbon.itp
>                                                       ffcharmmnb.itp
> these were added to "/usr/local/gromacs/share/gromacs/top"  and GMXLIB 
> path was set as
> "export GMXLIB=/usr/local/gromacs/share/gromacs/top"
> the 'pdb2gmx' command was run using the command:
> "pdb2gmx -f 1aoc-PPF.pdb -ff charmm -ignh -ter"
> but the following error message is coming
> "Library file ffcharmm.rtp not found in current dir nor in your GMXLIB 
> path."

It might be necessary to update FF.dat to include the line "ffcharmm 
  CHARMM 27"

You'll notice in the comments in my script that I point out that I'm not 
supplying any topology files - particularly residue topology files such 
as the missing .rtp causing your error. Unfortunately the link I 
provided to a source that does include such an .rtp file was on the old 
GROMACS webpage, and is no longer available - 

I have a copy of charmm_gromacs.tar.gz and am happy to mail this to 
anyone who inquires off-list.


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