<P>LAMMPS provides a ReaxFF potential file in its potentials dir, namely

potentials/ffield.reax.  Its format is identical to that used by van

Duin and co-workers.  It contains parameterizations for the following

elements: C, H, O, N, S, and Si.  You can use your another file in

elements: C, H, O, N, S (Si has been temporarily removed).

You can use another file in

place of it, and ReaxFF files with parameterizations for other

elements or for specific chemical systems may be available elsewhere.

</P>