[QE-users] ph.x from v6.3 reads wrong celldm

[RAPHAEL LONGUINHOS MONTEIRO LOBATO]

Sorry, I forgot to mention that the results or dispersion were obtained
using qe.6.3-bkp.

Best

On Wed, Mar 13, 2019, 15:04 Prof. Raphael Longuinhos Monteiro Lobato <
raphael.lobato at ufla.br> wrote:

> Hi,
>
> Back on the celldm post (sorry for the six months delay to reply ... I
> will bring back some parts to remember):
> http://lists.quantum-espresso.org/pipermail/users/2018-October/041418.html
>
> and
>
> http://lists.quantum-espresso.org/pipermail/users/2018-October/041419.html
>
> Previously, I wrote:
> +==
> ph.x from pre-release q-e-qe-6.3Max reads from outdir unexpected values
> for celldm and writes these in the header of .dyn . It leads to
> "rescaled" distances in .axsf and polarizability in the dynmat.x out
> (omega, IR, Raman tensor and depolarization factor are as expected).
> Hand-correcting the .dyn header (correct values for celldm) solves it.
>
> Tests in v6.2 and 6.2.2 leads to expected results (they read from outdir
> the expected values for celldm). ph.x prints wrong celldm while reading
> from outdir ... it is not related to io_dyn_mat write_dyn_mat_header ...
> also, the .xml files are the same.
> +==
>
> Prof. Giannozzi mentioned that
> https://gitlab.com/QEF/q-e/commit/9a579539b65bd1502d1f28747e483a1d1059f5f8
>
> could have solved the issue. Maybe I'm missing something, but it appears
> it did not.
>
> The issue on the celldm can lead to other unexpected differences on
> post-processing the dyn.
>
> In my case, the high-frequency (low frequency is okay) phonon dispersion
> near Gamma calculated with the original (wrong) celldm values and the
> ones using hand-correcting values are somewhat different. As example,
> the high-frequency LO mode obtained with the wrong cell_dm seems
> quadratic (or some d^2f/dk^2 >0 dependency) like using no LR
> electrostatics, while it becomes linear-like (I would expect some thing
> like that) when using the correct cell_dm. It is show in the images in
> appended. Also, there are some "discontinuities" in the branches I not
> used to see on results. Also, there are some extra inflection points in
> the region I show in the graphs that I would not expect (these appears
> using no LR electrostatics).
>
> Note: The system is expected to be polar semiconductor. In the graphs nq
> 07x07x01 and 14x14x01 uses nk is 14x14x1 (spacing of ~0.03*2pi/A).
> Later, I used both nk and nq of 16x16x01. Orange diamonds are direct 2D
> DFPT calculations (nk 14x14x01 or 16x16x01 leads to identical results in
> these direct 2D DFPT calculations). The highest frequency modes from
> direct 2D DFPT and from interpolation of dynmat are some what different
> (maybe the interpolation is not converged). Data with cell_dm corrected
> values are also indicated.
>
> I will repeat all these using those versions I reported correctly
> reading cell_dm values.
>
> Hope all it is not a "false alarm" (some unnoticed error of my part).
> Sorry bring problems, not solutions.
>
> Best,
>
> --
> Associate Professor Raphael Longuinhos Monteiro Lobato
> CV: http://lattes.cnpq.br/1475483971471395.
> Research Group site: http://jenainassoares2.wixsite.com/nanomat
> (Portuguese only - English version on the way)
> Departamento de Fisica, Universidade Federal de Lavras
> Av. Dr. Silvio Menicucci 1001, bairro Kenedy
> Post office box 3037
> 37200-000 - Lavras, MG, Brazil
>
>
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