Relax CG morphologies

After IBI potentials are generated, use these IBI potentials to relax the amorphous parts of the lattice morphology with This protocol performs the following steps:

  1. From CGMC or CGkMC output, identify crystalline regions and fill crystalline regions with COG+ representations based on COG+ files (center of geometry and orientation files, similar to the ones used as input for IBI potential generation) of phases A and B.
  2. Adapt grid densities in amorphous regions and fill amorphous regions with COG+ representations.
  3. Relax amorphous regions. During relaxations, crystalline regions are kept fixed, as they already have the correct COG distribution provided by the files in step 1.
  4. Print relaxed COG distribution as output for LightForge.


  • IBI potentials for mixed and pristine systems
  • COG and orientation file of a large crystal of each phase A and B. This crystal should exceed the size of the CG(k)MC grid by a factor 2. These will be rotated randomly and cut to the dimensions of each crystalline domain. These files can, like the input for the IBI fit, be generated from atomistic crystal structures.
  • From CG(k)MC: demixed SC lattice structure and orientation file indicating crystalline positions.

Run the relaxation

Please refer to the example in the "FromSCtoCOGplus/examples/RelaxSC" directory and adapt the settings file accordingly.

  • Prepare input files as described above.

  • copy IBI potential files

  • adapt the settings:

    • cryst_file_X, orientation_file_X: pristine crystal structures of phase A and B, COGs and orientations.
    • supply densities of phase a and b in particles/nm3
    • adapt nsteps and temperature for the relaxation
  • IBI-fit-parameters will be ignored in this step

  • run the relaxation:

    python settings

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