Lost atoms

Dear lammps users

I am trying to euilibrate Ni using reactive force field with a fixed bottom layer (gfreeze group)


  1. If I put “fix fixfreeze gfreeze setforce 0 0 0” after energy minimization then I am losing the atoms but if I put it before energy minimization then I am not losing any atoms why it that? I have seen the book “Computation Materials Science by June Gun Lee” and he did it after the energy minimization in page 72 “Nanodroplet of water wrapped by graphene nanoribbon”
    N.B. LAMMPS script is attached

ffield.reax.CHNi (5.85 KB)

in.relax.lmp (2.25 KB)

I don’t know why you are losing atoms. But if you want the bottom layer
to not be altered by the minimization, then you need to put the setforce
command before the minmize command.