[lammps-users] ERROR: Illegal tersoff parameter-Reg

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1

Dear lammps users
I am using windows version of lammps (lmp_windows.exe). I have found tersoff potential parameter for my simulation. I have created my tersoff potential file using those parameters similar to Si.TERSOFF file. When I am running the simulation, I am receiving the following error

“ERROR:Illegal Tersoff parameter”

I have given log and tersoff parameter file below. How to solve this?

log
LAMMPS (7 Apr 2010)
units metal
boundary p p p
atom_style atomic
echo both
lattice sc 5.0
Lattice spacing in x,y,z = 5 5 5

read_data ldf_sn_3nmnp.dat
orthogonal box = (10 0 0) to (60 60 60)
1 by 1 by 1 processor grid
510 atoms
510 velocities

timestep 0.01

mass 1 118.71

pair_style tersoff
pair_coeff * * Sn.tersoff Sn
ERROR: Illegal Tersoff parameter

tersoff potential file

element 1, element 2, element 3,

m, gamma, lambda3, c, d, costheta0, n, beta, lambda2, B, R, D, lambda1, A

Sn Sn Sn 3.0 1.0 0.0000 140000.0 14.5 0.0000 0.74
0.000000601 1.62 658.62 2.8 3.2 2.25 2848.0

please give me suggestions.

Thanks and regards

Karthik V

2

I have created my tersoff potential file using those parameters similar to Si.TERSOFF file
I am receiving the following error
"ERROR:Illegal Tersoff parameter"

I'm guessing your new param file has an invalid param.

Steve

3

Karthik,

D is greater than R in your parameters. That’s unphysical and triggered the error message.

Here is the relevant code fragment from pair_tersoff.cpp.

if (
params[nparams].lam3 < 0.0 || params[nparams].c < 0.0 ||
params[nparams].d < 0.0 || params[nparams].powern < 0.0 ||
params[nparams].beta < 0.0 || params[nparams].lam2 < 0.0 ||
params[nparams].bigb < 0.0 || params[nparams].bigr < 0.0 ||
params[nparams].bigd < 0.0 ||
params[nparams].bigd > params[nparams].bigr ||
params[nparams].lam3 < 0.0 || params[nparams].biga < 0.0 ||
params[nparams].powerm - params[nparams].powermint != 0.0 ||
(params[nparams].powermint != 3 && params[nparams].powermint != 1) ||
params[nparams].gamma < 0.0)
error->all(“Illegal Tersoff parameter”);

nparams++;
}

Zhun-Yong