<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 (
<span class="gmail-doi-field"><a href="https://doi.org/10.1103/PhysRevB.77.125218">https://doi.org/10.1103/PhysRevB.77.125218</a></span>
) 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_lr8nleas0" alt="image.png" width="371" height="117" class="gmail-CToWUd"></div><div>Here is the figure they generated <br></div><div><img src="cid:ii_lr8np7g31" alt="image.png" width="540" height="428" class="gmail-CToWUd gmail-a6T" tabindex="0"></div><div><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><font color="#888888"><div>Hasan</div></font>
</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">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>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></small></small></div>
</div>
<u></u><u></u>
_______________________________________________<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>
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