Dear Lammps users,
I am trying to use “fix setforce” command in order to fix two particles in a box. The only interaction between them is Lennard-Jones.
I try to define new variable for the component of force (the output of fix setforce) on each particle and print them to different file using fix print command.
When I check the Force on two particles, they are not equal and in the opposite direction according to the Newton’s third law. The surface to surface separation of two particles is almost 1/10 of the box length in order to decouple the pair particles from their periodic images.
I am wondering why the magnitude of the Force on each particle is not the same and why they are not in the opposite direction!!!
Shahzad