<div dir="ltr">Hi Dr. Paulatto,<div><br></div><div>Thank you so much for your suggestions. I was going in the wrong direction. So if I use your recommended code (<a href="https://anharmonic.github.io/thermal2/#d3_r2qx-code" target="_blank">https://anharmonic.github.io/thermal2/#d3_r2qx-code</a>), would I be able to generate the following figure for Bulk GaAs?</div><div><br></div><div><img src="cid:ii_lr9kww4i2" alt="image.png" width="528" height="455"><br></div><div><br></div><div>Actually my main goal is to calculate dielectric function at different temperatures (not 0 K).</div><div><br></div><div>Thanks</div><div>Md Jahid Hasan</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jan 11, 2024 at 9:19 AM Lorenzo Paulatto <<a href="mailto:lorenzo.paulatto@cnrs.fr">lorenzo.paulatto@cnrs.fr</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
<div style="padding-bottom:1px">
<p>Hello Jahid,</p>
<p>I have read the article very quickly, but I do not think they use
the RMS to compute epsilon. All they do is compute epsilon for a
few sample atomic potisions reached during the MD run, then they
average it. The "Theoretical Method" section does not have any
logic, but it is explained in the "Conclusions". The RMS seems to
be only used to ascertain the validity of the simulation.<br>
</p>
<div>hth</div>
<div><br>
</div>
<div>On 1/11/24 04:42, Md. Jahid Hasan Sagor
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Hi Dr. Paulatto,</div>
<div><br>
</div>
<div>Thank you so much for your comments.</div>
<div><br>
</div>
<div>Actually, The paper (attached) extracted the temperature of
each configuration from the mean square displacement per atom
of the configuration (GaAs). In the harmonic approximation,
they determined the relationship between
mean square displacement and temperature T from the phonon
density of states of bulk GaAs calculated by Giannozzi et al.
The equation as follows:
</div>
<div><br>
</div>
<div><img src="cid:ii_18cf9e71621cb971f161" alt="image.png" width="371" height="117"></div>
<div>Here is the figure they generated <br>
</div>
<div><img src="cid:ii_18cf9e71621cb971f162" alt="image.png" width="540" height="428"><br>
</div>
<div><br>
</div>
<div>So, now If I can find out the RMS of GaAs using CPMD, I
will try to observe the corresponding configuration of GaAs
atoms. Finally, the atomic positions will be the input of
Quantum Espresso pw.x etc ( I mean normally how do we
calculate dielectric constant in QE).</div>
<div><br>
</div>
<div>Can I use it (
<a href="https://anharmonic.github.io/thermal2/#d3_r2qx-code" target="_blank">https://anharmonic.github.io/thermal2/#d3_r2qx-code</a>)
for the same purpose?
</div>
<div><br>
</div>
<div>Best</div>
<div>Hasan<br>
</div>
<div> </div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Jan 10, 2024 at
3:13 PM Lorenzo Paulatto <<a href="mailto:lorenzo.paulatto@cnrs.fr" target="_blank">lorenzo.paulatto@cnrs.fr</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div style="padding-bottom:1px">
<p>I would guess that you calculate the static dielectric
constant at the temperature-dependent volume
(experimental, or quasi-harmonic) and you are 90% of the
way there. Do you have a specific reason to believe that
it would be proportional to the RMS ?</p>
<p>Btw, the code d3_r2q.x included with the "anharmonic"
package can compute the RMS from an inexpensive phonon
calculation, maybe have a look at it before doing a large
supercell MD.</p>
<p><a href="https://anharmonic.github.io/thermal2/#d3_r2qx-code" target="_blank">https://anharmonic.github.io/thermal2/#d3_r2qx-code</a><br>
</p>
<div>cheers<br>
</div>
<div><br>
</div>
<div>On 10/01/2024 19:35, Md. Jahid Hasan Sagor wrote:<br>
</div>
<blockquote type="cite">
<div dir="auto">
<div>Actually, I have to calculate Dielectric constant
for GaAs for different temperatures (not 0 k). To do
that, I need to extract atomic positions for different
RMS using CPMD. If anyone know someone/ or give some
guidelines, it would be great help for me.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Thank you.<br>
<br>
<div class="gmail_quote" dir="auto">
<div dir="ltr" class="gmail_attr">On Tue, Jan 9,
2024, 2:09 PM Md. Jahid Hasan Sagor <<a href="mailto:md.sagor@maine.edu" target="_blank">md.sagor@maine.edu</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">Dear QE community,
<div><br>
</div>
<div>I want to calculate the mean square
displacement of GaAs using CPMD. From the mean
square displacement, I want to extract the
configuration of atoms (e.g atomic position of
Ga and As). Could anyone please give me some
guidelines on how I can perform it? Should I
use only the cp.x package or by other means?
Your time and suggestions would be a great
help for me.</div>
<div><br>
</div>
<div>Best Regards</div>
<div>Md Jahid Hasan</div>
<div>PhD Student, Mechanical Engineering</div>
<div>University of Maine</div>
</div>
</blockquote>
</div>
</div>
</div>
<br>
<fieldset></fieldset>
<pre>_______________________________________________
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</blockquote>
<div>-- <br>
<small>Dr. Lorenzo Paulatto<br>
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université<br>
phone: +33 (0)1 442 79822 / skype: paulatz<br>
<a href="http://www.impmc.upmc.fr/~paulatto/" target="_blank">http://www.impmc.upmc.fr/~paulatto/</a>
- <a href="https://anharmonic.github.io/" target="_blank">https://anharmonic.github.io/</a><br>
23-24/423 B115, 4 place Jussieu 75252 Paris CX 05</small></div>
</div>
_______________________________________________<br>
The Quantum ESPRESSO community stands by the Ukrainian<br>
people and expresses its concerns about the devastating<br>
effects that the Russian military offensive has on their<br>
country and on the free and peaceful scientific, cultural,<br>
and economic cooperation amongst peoples<br>
_______________________________________________<br>
Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu" rel="noreferrer" target="_blank">www.max-centre.eu</a>)<br>
users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="noreferrer" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></blockquote>
</div>
</blockquote>
<div>-- <br>
<small>Dr. Lorenzo Paulatto<br>
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université<br>
phone: +33 (0)1 442 79822 / skype: paulatz<br>
<a href="http://www.impmc.upmc.fr/~paulatto/" target="_blank">http://www.impmc.upmc.fr/~paulatto/</a>
- <a href="https://anharmonic.github.io/" target="_blank">https://anharmonic.github.io/</a><br>
23-24/423 B115, 4 place Jussieu 75252 Paris CX 05<small></small></small></div>
</div>
<u></u><u></u>
</blockquote></div>