I have now upgraded the LAMMPS version and got rid of the 'illegal
create_atoms command' error. Valeria was right to point that out. Thanks to
everyone for your suggestions. Now I having a major problem, which I can't
make out why. It would be great if you could throw some light on this.
The Ag core of 441 atoms (radius 3 lattice units) equilibrated quickly. But
then when I introduced single silver atom at radius 6 lattice units and gave
it a small velocity toward the core, the temperature (and thus kinetic energy)
started going down rapidly when the single Ag atom came closer to the surface
of the core and entered its subsurface. The temperature went to zero when run
for longer time. There is just the Ag core and one Ag atom approaching it,
with vacuum in between. Could anyone give me a hint why the system is losing
energy. I have pasted my input file here.
Your help would be much appreciated.