My understanding of the workings of Amber is a little shaky, but I think you want <your Chimera installation>/bin/amber11/dat/leap/parm/gaff.dat. It's certainly one of the files in that parm directory at least.

Eric Pettersen

UCSF Computer Graphics Lab

http://www.cgl.ucsf.edu

On Jul 13, 2010, at 2:21 AM, Jean Didier Pie Marechal wrote:

HI guys,

I am trying to add another type of atom in the GAFF parameter file that is called during the minimization process and can't find the right place.

Could you give me a hand please?

best,
JD