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<p>Dear Erik,</p>
<p>you question is extremely vast and would require hours to answer
in detail. </p>
<p>The starting point for the theory used in QE is the "code" paper
doi:10.1088/0953-8984 and reference 46 therein: NIelsen &
Martin 10.1103/PhysRevB.32.3780. There are more, quite complicated
therms related to ultrasoft pseudoptentials.</p>
<p class="MsoNormal">- Are the dependencies of the cell vectors on
the reciprocal lattice vectors G taken into account during a
vc-relaxation?
</p>
<p class="MsoNormal"><br>
</p>
<p class="MsoNormal">no, but relax is done at constant number of
plane waves (not constant cutoff) </p>
<p class="MsoNormal"><br>
</p>
<p class="MsoNormal">- If so, how is the coupling between these
terms treated? </p>
<p class="MsoNormal"><br>
</p>
<p class="MsoNormal">I'm not sure what you mean, but I think there
is not</p>
<p class="MsoNormal"><br>
</p>
<p class="MsoNormal">- Are the analytical gradients completely
expressed in cartesian coordinates?</p>
<p class="MsoNormal"><br>
</p>
<p>Is there are many terms (hartree, XC, local, gradient
correction...) it is very possible that some terms are computed in
cartesian coordinates, others on the basis of lattice vectors.
From a quick look at the code, I think they are mostly done
directly in cartesian coordinates.</p>
<p>hth</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 11/11/25 17:12, Erik Hansen via
users wrote:<br>
</div>
<blockquote type="cite"
cite="mid:025734f701e240498761201224267f19@dlr.de">
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<p class="MsoNormal">Dear Quantum ESPRESSO users and developers,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am writing to follow up on my previous
inquiry.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">As I am currently working at the code level
with Quantum ESPRESSO, I am particularly interested in
understanding how the analytical gradients are handled
internally during a variable-cell (vc-) relaxation.
Specifically:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">- Are the dependencies of the cell vectors
on the reciprocal lattice vectors G taken into account during
a vc-relaxation?
<o:p></o:p></p>
<p class="MsoNormal">- If so, how is the coupling between these
terms treated? <o:p>
</o:p></p>
<p class="MsoNormal">- Are the analytical gradients completely
expressed in cartesian coordinates?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you very much for your time and
assistance,<o:p></o:p></p>
<p class="MsoNormal"><span lang="DE"
style="font-size:12.0pt;mso-fareast-language:EN-GB">Best
regards<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE"
style="font-size:12.0pt;mso-fareast-language:EN-GB">Erik
Hansen<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE"
style="font-size:12.0pt;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE"
style="font-size:12.0pt;color:dimgray;mso-fareast-language:EN-GB">——————————————————————————</span><b><span
lang="DE"
style="font-size:12.0pt;font-family:"Arial",sans-serif;color:dimgray;mso-fareast-language:AR-SA"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span lang="DE"
style="font-size:12.0pt;font-family:"Arial",sans-serif;color:dimgray;mso-fareast-language:AR-SA">Deutsches
Zentrum für Luft- und Raumfahrt</span></b><span lang="DE"
style="font-size:12.0pt;color:dimgray;mso-fareast-language:EN-GB"> e. V.
(DLR)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;color:dimgray;mso-fareast-language:EN-GB">German
Aerospace Center<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:16.0pt"><span
lang="EN-US"
style="font-size:8.5pt;font-family:"Arial",sans-serif;color:dimgray;mso-fareast-language:AR-SA">Institute
for Frontier Materials on Earth and in Space | Linder Höhe |
51147 Köln | Germany</span><span lang="EN-US"
style="font-size:8.5pt;font-family:"Arial",sans-serif;mso-fareast-language:AR-SA"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"
style="font-size:12.0pt;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"
style="font-size:12.0pt;color:dimgray;mso-fareast-language:EN-GB">M.Sc.
</span><b><span lang="EN-US"
style="font-size:12.0pt;font-family:"Arial",sans-serif;color:dimgray;mso-fareast-language:AR-SA">Erik
Hansen</span></b><span lang="EN-US"
style="font-size:12.0pt;color:dimgray;mso-fareast-language:EN-GB">
(he/him) |
</span><span lang="EN-US"
style="font-size:8.5pt;color:dimgray;mso-fareast-language:EN-GB">Researcher</span><span
style="font-size:8.5pt;color:dimgray;mso-fareast-language:EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:16.0pt"><span
style="font-size:8.5pt;color:dimgray;mso-fareast-language:EN-GB">Telephone
+49 123 123-4567 |</span><span
style="font-size:8.5pt;mso-fareast-language:EN-GB">
</span><span lang="EN-US"
style="font-size:8.5pt;mso-fareast-language:EN-GB"><a
href="mailto:erik.hansen@dlr.de" moz-do-not-send="true"><span
style="color:#005AA5">erik.hansen@dlr.de</span></a></span><span
style="font-size:10.0pt;mso-fareast-language:EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:8.5pt;color:dimgray;mso-fareast-language:EN-GB">Feel
free to let me know which pronouns you would like to be
addressed with.<o:p></o:p></span></p>
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style="font-size:12.0pt;mso-fareast-language:EN-GB"><a
href="http://www.DLR.de/" moz-do-not-send="true"><span
lang="EN-US" style="font-size:8.5pt;color:#005AA5">DLR.de</span></a></span><span
lang="EN-US"
style="font-size:10.0pt;mso-fareast-language:EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"
style="font-size:12.0pt;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span
lang="EN-US"
style="font-size:7.0pt;color:#737373;mso-fareast-language:DE">DLR is
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can provide information (</span><span
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<p class="MsoNormal"><o:p> </o:p></p>
</div>
<br>
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<pre wrap="" class="moz-quote-pre">_______________________________________________________________________________
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<div class="moz-signature">-- <br>
<small>Dr. Lorenzo Paulatto<br>
IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN <br>
phone: +33 (0)1 442 79822 / telegram: lpaulatto<br>
<a href="http://www.impmc.upmc.fr/~paulatto/"
class="moz-txt-link-freetext">http://www.impmc.upmc.fr/~paulatto/</a>
- <a href="https://anharmonic.github.io/"
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