I have a simulation cell with a grain boundary and two fixed regions above and below the cell. I was trying to apply a constant force to the upper fixed region. However, I am getting an error about lost atoms.
The way I apply force is by first making the fixed region a rigid body (turning off the torque) and then using addforce command.
fix bg r rigid group 1 r torque 1 off off off
fix zfr r addforce 0.0073784 0.0 0.0 (my units are metal so force is in eV/A)
In order to fix this problem I tried the following:
1- Reducing the magnitude of the force
2- Decreasing the timestep
3- Updating neighbor list every step using neigh_modify every 1
However, none of these seem to solve my problem. I am also attaching my input file with this email. I would really appreciate if somebody can help me with this.