Reviewing the Fix Orient/FCC class

In this section, we will discuss how the orientations of two adjoining grains are compared to determine forces that generate grain boundary migration.

This fix applies a force to atoms located at the interface of two planar grains, that is, the grain boundary, to account for a range of potential energies that may be added to these atoms based on their neighboring atom positions. It is assumed that the two grains are face-centered cubic (FCC) crystals with different orientations, with their orientation vectors defined in two separate files. Altogether, this force results in atoms being migrated from one grain to the other.

The Fix Orient/FCC source code files, fix_orient_fcc.cpp and fix_orient_fcc.h, are located inside the MISC folder and need to be compiled as a separate package. The syntax for implementing this fix in a LAMMPS input script involves several input parameters:

fix  FIX_ID  GROUP_ID  orient/fcc...