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    <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 class="moz-txt-link-freetext" href="https://anharmonic.github.io/thermal2/#d3_r2qx-code">https://anharmonic.github.io/thermal2/#d3_r2qx-code</a><br>
    </p>
    <div class="moz-cite-prefix">cheers<br>
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    <div class="moz-cite-prefix"><br>
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    <div class="moz-cite-prefix">On 10/01/2024 19:35, Md. Jahid Hasan
      Sagor wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAC5Hid_jL0qvEWs3RnBD7r8chXmQb0ZHRdBZTAk0u4x8ihFkNw@mail.gmail.com">
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        <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>
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        <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" moz-do-not-send="true"
                class="moz-txt-link-freetext">md.sagor@maine.edu</a>>
              wrote:<br>
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            <blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px #ccc solid;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>
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
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    </blockquote>
    <div class="moz-signature">-- <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/"
          class="moz-txt-link-freetext">http://www.impmc.upmc.fr/~paulatto/</a>
        - <a href="https://anharmonic.github.io/"
          class="moz-txt-link-freetext">https://anharmonic.github.io/</a><br>
        23-24/423 B115, 4 place Jussieu 75252 Paris CX 05<small></small></small></div>
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