Dear LAMMPS users,

I am trying to insert a new group of atoms into an existing simulation box by deleting atoms that initially occupied the position in which the new group would be located. I intend to introduce a hybrid potential such that the existing atoms are SW si and the new atoms would be modeled by TERSOFF si potential and the interaction between the 2 different si groups will be modeled by Ziegler.

*units metal*

*dimension 3*

*boundary p p p*

*atom_style atomic*

*newton on*

*lattice diamond 5.4307 orient x 1 0 -1 orient y -1 2 -1 orient z 1 1 1*

*neighbor 2.0 bin*

*neigh_modify every 1 delay 0 check yes*

*read_data fs_sol.data #TI_sol.data*

*region solid block INF INF INF INF 0 8 units lattice*

*region cleave1 block INF INF INF INF 3.828 4.215 units lattice*

*group sol region solid*

*group wall region cleave1*

*pair_style hybrid sw tersoff ziegler 2.0*

*pair_coeff * * sw si.sw Si NULL*

*pair_coeff * * tersoff Si.tersoff NULL Si*

*pair_coeff 1 2 ziegler 14 14 3.0*

*mass 1 28.0855*

*mass 2 28.0855*

*delete_atoms group wall*

*create_atoms 2 region cleave1*

*compute x all property/atom x*

*compute k all ke/atom*

*compute p all pe/atom*

*compute cc all chunk/atom bin/1d z lower 1 units lattice*

*variable kb equal 8.617339e-5*

*variable temp atom c_k/(1.5*v_kb)*

*variable atomEng atom c_k+c_p*

*dump id all custom 1000 step_1.d id x y z c_k c_p v_temp v_atomEng type vx vy vz*

*log step_1.log*

*thermo_style custom step temp press ke pe density enthalpy lx ly lz*

*thermo 1000*

*restart 20000 restart_step1_1 restart_step1_2*

*minimize 1.0e-4 1.0e-6 100 1000*

*fix 1 all nvt temp 1685 1685 1*

*run 100000*

*unfix 1*

*undump id*

I ran the input file above on 06 Jan 2017 LAMMPS version and got the error message **"ERROR: Illegal pair_style command (…/pair_tersoff.cpp:285)’'**

Please, I would appreciate suggestions from you all on how to go about setting up my simulation.

Regards,