[Phonopy-users] Need help to used modulation command

[Naveena P.S. <nav...@gm...>]

Hello
I am trying to do atomic modulation (atomic displacement) with respect to
the normal mode at the specific q point. I tried to use this command line:
phonopy --qe --modulation 2 2 1, 0.000000000   0.433012702   0.000000000 1
0.03 0 -c TiS2_primitive_scf.in --dim 2 2 1 -v.

But it provides error like this:

phonopy --qe --modulation 2 2 1, 0.000000000   0.433012702   0.000000000 1
0.03 0 -c TiS2_primitive_scf.in --dim 2 2 1 -v
        _
  _ __ | |__   ___  _ __   ___   _ __  _   _
 | '_ \| '_ \ / _ \| '_ \ / _ \ | '_ \| | | |
 | |_) | | | | (_) | | | | (_) || |_) | |_| |
 | .__/|_| |_|\___/|_| |_|\___(_) .__/ \__, |
 |_|                            |_|    |___/
                                      2.47.1

-------------------------[time 2026-02-06 16:53:41]-------------------------
Compiled with OpenMP support (max 8 threads).
Python version 3.11.11
Spglib version 2.7.0

Calculator interface: qe
Crystal structure was read from "TiS2_primitive_scf.in".
Unit of length: au
Modulation mode
Settings:
  Supercell: [2 2 1]
Spacegroup: P-3m1 (164)
Number of symmetry operations in supercell: 48
------------------------------ primitive cell ------------------------------
Lattice vectors:
  a    6.460973493253429    0.000000000000000    0.000000000000000
  b   -3.230486746626715    5.595367178253872    0.000000000000000
  c    0.000000000000000    0.000000000000000   34.015070466894429
Atomic positions (fractional):
   *1 Ti  0.00000000000000  0.00000000000000  0.50000000000000  47.867
   *2 S   0.66666700000000  0.33333300000000  0.57891028530000  32.065
    3 S   0.33333300000000  0.66666700000000  0.42108971470000  32.065
-------------------------------- unit cell ---------------------------------
Lattice vectors:
  a    6.460973493253429    0.000000000000000    0.000000000000000
  b   -3.230486746626715    5.595367178253872    0.000000000000000
  c    0.000000000000000    0.000000000000000   34.015070466894429
Atomic positions (fractional):
   *1 Ti  0.00000000000000  0.00000000000000  0.50000000000000  47.867 > 1
   *2 S   0.66666700000000  0.33333300000000  0.57891028530000  32.065 > 2
    3 S   0.33333300000000  0.66666700000000  0.42108971470000  32.065 > 3
-------------------------------- super cell --------------------------------
Lattice vectors:
  a   12.921946986506859    0.000000000000000    0.000000000000000
  b   -6.460973493253429   11.190734356507743    0.000000000000000
  c    0.000000000000000    0.000000000000000   34.015070466894429
Atomic positions (fractional):
   *1 Ti  0.00000000000000  0.00000000000000  0.50000000000000  47.867 > 1
    2 Ti  0.50000000000000  0.00000000000000  0.50000000000000  47.867 > 1
    3 Ti  0.00000000000000  0.50000000000000  0.50000000000000  47.867 > 1
    4 Ti  0.50000000000000  0.50000000000000  0.50000000000000  47.867 > 1
   *5 S   0.33333350000000  0.16666650000000  0.57891028530000  32.065 > 2
    6 S   0.83333350000000  0.16666650000000  0.57891028530000  32.065 > 2
    7 S   0.33333350000000  0.66666650000000  0.57891028530000  32.065 > 2
    8 S   0.83333350000000  0.66666650000000  0.57891028530000  32.065 > 2
    9 S   0.16666650000000  0.33333350000000  0.42108971470000  32.065 > 3
   10 S   0.66666650000000  0.33333350000000  0.42108971470000  32.065 > 3
   11 S   0.16666650000000  0.83333350000000  0.42108971470000  32.065 > 3
   12 S   0.66666650000000  0.83333350000000  0.42108971470000  32.065 > 3
----------------------------------------------------------------------------
  ___ _ __ _ __ ___  _ __
 / _ \ '__| '__/ _ \| '__|
|  __/ |  | | | (_) | |
 \___|_|  |_|  \___/|_|.

Also, it creates modulation.conf which contains:
DIM = 2 2 1
MODULATION = 2 2 1, 0 0.433012702 0 1 0.03 0.

Also, I found this idea from:
https://phonopy.github.io/phonopy/setting-tags.html.

Just today I started to use this package and I found your youtube videos
discussing how to use phonopy with qe. So I thought I could ask for some
help. kindly help me if you have any ideas.

with regards
Naveena P.