Hi, everybody,
I’ve been trying to convert the EAM potential of Co in the setfl formatted “CoAl.eam.alloy” file to a separate funcfl formatted “.eam” file. It seems that the only problem lying behind is the pair potential. In setfl format it is expressed as "rphi" and in funcfl it is expressed as “effective charge Z”
After reading the lammps manual and the “pair_eam.cpp”, “pair_eam_alloy.cpp” files, I though I found the relation between the above expressions:
rphi = 27.2 * 0.529 * Zi * Zj (http://lammps.sandia.gov/doc/pair_eam.html)
For the interaction of same kind of atoms at certain distance, this relation seems hold: Z^2 = rphi/(27.20.529). And the right hand side of this equation seems nonnegative.
But in the “CoAl.eam.alloy” file, the r*phi function has negative values!
Hence, it brought up the following questions, I’d really appreciate it if someone can help me with them.

Is there a way to convert the potential of a single element in the setfl formed file into a funcfl formated file?

If my statements above are true, then when lammps is dealing with funcfl files, for the interaction of the same kind of atoms are the calculated r*phi values non negative?
Thanks,