ClayFF in LAMMPS

Dear All,

I am trying to implement ClayFF in LAMMPS. ClayFF uses a 12-6 LJ function to define VDW interactions. If you check out the LJ term in ClayFF (Cygan et al. 2003), you will notice that it is formulated quite differently from available 12-6 LJ “pair_styles” in lammps, particularly the coefficients of the short-range repulsion and the attractive dispersion terms.

ClayFF 12-6 LJ: D*[ (sigma/r)^12 – 2*(sigma/r)^6]

LAMMPS 12-6 LJ pair_styles: D*[ (sigma/r)^12 – (sigma/r)^6]

Am I right? or am I missing something here?

Now, if there is no such pair style in LAMMPS, a new pair style, very similar to “lj/cut/coul/cut” must be defined, which is coded in “pair_lj_cut_coul_cut.cpp” and “pair_lj_cut_coul_cut.hp” files in lammps source directory. The only difference would be the coefficients before repulsive and attractive terms. Does anybody have access to such corrected files? If I want to apply the corrections myself. Is it enough to change line #280 in pair_lj_cut_coul_cut.cpp?

Thank you,

Navid

Navid Sakhavand
Graduate Research Assistant
Department of Civil and Environmental Engineering
Rice University, Houston, TX 77005
[email protected]…623…

I suggest you contact Randy Cygan or Jeff Greathouse (CCd) in
the same group and ask them if/how they do ClayFF with LAMMPS.

Steve