quantum-espresso/PHonon/FD/example

Illustrates the calulations needed to generate the interatomic force constants file

by using the finite displacements method



1) make a self-consistent calculation 

   cd $espresso_dir/PHonon/FD/example/inputfiles

   $espresso_dir/bin/pw.x < si.scf.in > si.scf.out

  

2) create finite displacements in a supercell

   $espresso_dir/bin/fd.x < fd.in > fd.out



3) run all the finite displacements and extract the forces

   sh ../../run_fd 



4) generate the file "si_ifc.fc" of the interatomic force constants

   $espresso_dir/bin/fd_ifc.x < fd_ifc.in

   cat ./fd_files/header.txt > si_ifc.fc

   echo "F" >> si_ifc.fc

   cat ./silicon_ifc.fc >> si_ifc.fc