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Welcome to Thermo_pw

Ab-initio computation of material properties

THERMO_PW QUICK HELP

In order to use thermo_pw you need a working version of the Quantum ESPRESSO (QE) package. Thermo_pw can be downloaded from its main page as a .tar.gz file. The current production version is 1.1.1 compatible with QE-6.4.1. The thermo_pw file should be copied in the main (QE) directory and unpacked with the command:

tar -xzvf thermo_pw.1.1.1.tar.gz

This command produces a directory called thermo_pw. To compile the code you need a Fortran compiler, for instance the gcc package and gfortran (or gcc-fortran in some distributions), and the same libraries required by QE. After getting the directory thermo_pw in the main QE directory, cd to the directory thermo_pw and give the command make join_qe. Then cd to the main QE directory and compile thermo_pw with the command:

make thermo_pw

To run thermo_pw it is useful to have the gnuplot package, and to plot the Brillouin zone you need the asymptote package. Both are available as precompiled packages in many distributions. For further information, please refer to the user's guide available in the thermo_pw/Doc directory. Please report any problem to dalcorso .at. sissa.it.

The development version of thermo_pw is hosted at https://github.com/dalcorso/thermo_pw. To download it you need the git package. Then you can give the command:

git clone https://github.com/dalcorso/thermo_pw

and you should get a directory called thermo_pw that contains the source code. The git version can be used only together with the version of QE reported here: 6.4.1. Please note that sometimes the git version is not working properly and in any case its use is not recommended.

Although thermo_pw has been used for several years and can be considered reasonably stable, it remains an experimental code given as it is. If you are running a version of QE older than 6.4.1 you can still use thermo_pw but you should carefully match the versions of thermo_pw and of QE as explained in the main thermo_pw page.

Before using thermo_pw, please apply the patches given below.

Patches for thermo_pw.1.1.1:

Patches for thermo_pw.1.0.0:

Known problems of thermo_pw.0.9.0:

Patches for thermo_pw.0.9.0:

Patches for thermo_pw.0.8.0:

Patches for thermo_pw.0.7.0:

Patches for thermo_pw.0.6.0:

Patches for thermo_pw.0.5.0:

Patches for thermo_pw.0.4.0:

Patches for thermo_pw.0.3.0:

Patches for thermo_pw.0.2.0:

Patches for thermo_pw.0.1.0:

FAQ:

  1. How can I learn to use thermo_pw?
    Please learn the basic use of Quantum ESPRESSO first. Then you can read the thermo_pw tutorial and user’s guide and run the examples. These FAQ assume that you have a basic understanding of thermo_pw and contain miscellaneous information not available in the user’s guide.

  2. Can I study the thermal expansion of anisotropic solids using thermo_pw?
    For some crystal systems, yes, but not all systems are supported or tested. Read carefully the user’s guide and use a version higher than 0.3.0. Also use dynamical matrices in .xml format or the calculation of thermal expansion with Gruneisen parameters will not work with all versions previous to 0.5.0.

  3. Can I calculate the temperature dependence of the band gap or in general of the band structure using thermo_pw?
    You can calculate the band structure at the crystal geometry that corresponds to a given temperature. In this way you evaluate the effect of thermal expansion on the band structure or on the gap. However an important temperature dependence of the band gaps and of the band structure comes from the electron-phonon interactions that are not included in thermo_pw. For this purpose you should use another package.

  4. Can I calculate the equilibrium geometry of a solid at a given temperature using thermo_pw?
    Yes, but the calculation is as heavy as computing the anharmonic properties and it will take a lot of time and resources. You need to learn how to use thermo_pw before starting such a complex calculation.

  5. Which is the difference between examples and inputs?
    Examples illustrate the features of thermo_pw and are fast, but are not converged. inputs are more realistic examples.

  6. Sometimes the examples of thermo_pw run correctly, sometimes they crash. Which is the problem?
    The most probable reason is that you have not removed the results directory produced by a previous run of the example script.

  7. make thermo_pw is not working. Compilation stops with some missing routines error.
    Most probably you have not matched the versions of QE and of thermo_pw.

  8. I have compiled thermo_pw but as I run it, it stops immediately. I am using thermo_pw.0.3.0.
    Most probably you have not applied the patch described above. Update to a newer version.

  9. I cannot run the examples. I have problems using images. What should I do?
    If you want to run the examples without images edit the file environment_variables in the main QE directory. Search the two variables PARA_IMAGE_PREFIX and PARA_IMAGE_POSTFIX and set -ni 1.

  10. I have not a parallel computer. I do not know what mpi is. Can I run thermo_pw?
    Only thermo_pw.0.5.0 or later versions can be compiled in serial. All previous versions must be compiled together with mpi.

  11. An ionic relaxation converges with pw.x but not with thermo_pw.x (version 0.4.0).
    This is a bug of version 0.4.0. Please apply the same changes as in the commit 197343 or update to a newer version.

  12. The plot of the phonon dispersions is very strange with several disjoint parts. Moreover the modes are not classified using symmetry. Why?
    The mode symmetry analysis requires dynamical matrices in .xml format. Please put the .xml extension in the fildyn variable in the ph.x input. Symmetry matrices are needed also to recognize symmetry equivalent point on the Brillouin zone.

  13. The plot of the Gruneisen parameters has strange crossings in some points. Why?
    In some cases the plot of the Gruneisen parameters needs more accuracy on the symmetry analysis than the phonon plot. Accidentally degenerate frequencies might have very different Gruneisen parameters. Change the parameter 5.D-2 at line 148 of PHonon/PH/find_mode_sym.f90 to 1.D-2 or less and recompile thermo_pw.

  14. Thermo_pw documentation does not compile and stops with an error saying that html.sty is missing or latex2html is missing.
    This is not a problem of thermo_pw. In order to compile the documentation thermo_pw needs a quite complete latex package. You can find html.sty on the web and copy it inside thermo_pw/Doc directory and you can install latex2html. Even if you do not solve this problem, thermo_pw.x will be available in the bin directory of QE. Only the documentation will be missing.

  15. The plot of the projected band structure has some problems. Some gaps have the same color of the projected band structure.
    This is a problem of old versions of gnuplot. Update to gnuplot 5.0 or higher.

  16. The phonon dispersion plot seems strange, some branches are missing.
    Please check that you used enough digits for the atomic positions. A typical problem appears when you write 1/3 and 2/3 in single precision. The pw.x code finds more symmetries than those that are actually present in the final modes and the routine that identifies the mode symmetry gets confused.

  17. The code fails to identify the space group and stops with an error ‘‘point group orientation uncorrect’’.
    Most probably you are simulating a noncollinear magnetic system. Magnetic space group identification is not implemented but no check is done in versions up to 0.9.0. Please make the same changes as commit a68e6cb of 18 January 2018. If you find this error, you are using ibrav/=0, and your system is collinear, please send me your input.

  18. what='scf_disp' and partial phonon computations with start_q, last_q or start_irr last_irr gives strange error messages.
    The option what='scf_disp' requires all the dynamical matrices files in the dynamical_matrices directory. Use what='scf_ph' until you collect all the dynamical matrices and do a final run with what='scf_disp'.

  19. I am computing a phonon dispersion but some q points are not computed.
    Most probably you have not cleaned the outdir directory. Note that the thermo_pw always tries to use the content of the outdir directory if present.

  20. Is it possible to increase the temperature range?
    Yes, you have to remove the therm_files directory while keeping the dynamical_matrices and the restart directories. If you removed the outdir directory, use after_disp=.TRUE. and set fildyn with the name of the dynamical matrices.

  21. Is it possible to increase the number of points used to compute the phonon dos?
    Yes, you have to remove both the phdisp_files and the therm_files directories while keeping the dynamical_matrices and the restart directories.

  22. I made a calculation with with_eigen=.FALSE.. Is it possible to restart with with_eigen=.TRUE.?
    Yes, but you have to remove both the phdisp_files and the therm_files directories, while keeping the dynamical_matrices and the restart directories.