code: def write_aims(filename, atoms):
      
  
      lines = ""
      lines += "# geometry.in for FHI-aims \n"
      lines += "# | generated by phonopy.FHIaims.write_aims() \n"
  
      lattice_vector_line = "lattice_vector " + "%16.16f "*3 + "\n"
      for vec in atoms.get_cell():
          lines += lattice_vector_line % tuple(vec)
  
      N = atoms.get_number_of_atoms()
  
      atom_line = "atom " + "%16.16f "*3 + "%s \n"
      positions = atoms.get_positions()
      symbols = atoms.get_chemical_symbols()
  
      initial_moment_line = "initial_moment %16.6f\n"
      magmoms = atoms.get_magnetic_moments()
  
      for n in range(N):
          lines += atom_line % (tuple(positions[n]) + (symbols[n],))
          if magmoms is not None:
              lines += initial_moment_line % magmoms[n]
  
      with open(filename, 'w') as f:
          f.write(lines)
docs: Method to write FHI-aims geometry files in phonopy context.