Hi LAMMPS users,
I am trying to compute the friction force between two surfaces whose interactions are defined by the Tersoff potential. In the LAMMPS documentation, it says that the compute group/group command cannot accurately describe forces between two groups with 3-body and other many-body potentials.
I think I can accomplish the same thing using the “variable group fcm()” or “compute reduce fx” commands. Do the forces calculated by these commands have the same restrictions on 3-body and many-body potentials? If so, is there a better way to calculate the forces between two Tersoff surfaces?
Thanks,
Michael
Hi LAMMPS users,
I am trying to compute the friction force between two surfaces whose
interactions are defined by the Tersoff potential. In the LAMMPS
documentation, it says that the compute group/group command cannot
accurately describe forces between two groups with 3-body and other
many-body potentials.
true. because compute group/group loops over all pairs of atoms
between those two groups and computes the individual (pairwise)
interactions and sums them up. so that won't work with manybody
potentials.
I think I can accomplish the same thing using the "variable group fcm()" or
"compute reduce fx" commands.
i think so, too.
Do the forces calculated by these commands
have the same restrictions on 3-body and many-body potentials?
no. this is just taking the forces on the individual atoms and sums
them up. if this would not work, you could not use a manybody
potential in LAMMPS at all.
axel.