1# Example of the CP2K Phonopy interface for NaCl 2 3To create supercells with displacements: 4 5```console 6$ phonopy --cp2k -c NaCl.inp -d --dim="2 2 2" 7``` 8 9A perfect 2x2x2 supercell (`NaCl-supercell.inp`) and two 2x2x2 supercells 10(`NaCl-supercell-001.inp`, resp. `NaCl-supercell-002.inp`) of the conventional 11unit cell written in `NaCl.inp` are created. 12In addition, `phonopy_disp.yaml` file is created. 13 14The `amplitude` option is optionally specified for atomic displacement distance 15in Angstrom. After force the calculations with the crystal structures in 16NaCl-supercell-xxx.inp, it is needed to create `FORCE_SETS` file by running 17 18```console 19$ phonopy --cp2k -f NaCl-supercell-001-forces-1_0.xyz NaCl-supercell-002-forces-1_0.xyz 20``` 21 22Here the XYZ files are supposed to contain the forces on atoms calculated 23by CP2K. The `phonopy_disp.yaml` file has to be put in the current directory. 24Now you can run phonon calculation, e.g., 25 26```console 27$ phonopy --cp2k -c NaCl.inp -p band.conf 28``` 29