<div dir="auto"><div>Dear Barnali,</div><div dir="auto">There is no LO-TO splitting in graphene, or more precisely, it is zero.</div><div dir="auto"><br></div><div dir="auto">Kind regards<br><br><div data-smartmail="gmail_signature" dir="auto">-- <br>Lorenzo Paulatto<br>Written on a virtual keyboard with real fingers</div><div class="gmail_extra" dir="auto"><br><div class="gmail_quote">On 30 Nov 2017 3:59 pm, "Barnali Bhattacharya" <<a href="mailto:barnalidgbhatt@gmail.com">barnalidgbhatt@gmail.com</a>> wrote:<br type="attribution"><blockquote class="quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="color:black"><font face="times new roman, serif">Dear QE USERS,<span></span></font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="color:black"><span><font face="times new roman, serif"> </font></span></span></p>

<pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">I am trying to reproduce the </span>phonon dispersion with <span style="color:black">LO-TO splitting of graphene </span><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">by using quantum espresso code.</span>  </font></pre><pre><font face="times new roman, serif">To get LO-TO splitting, I have <span style="color:black">added epsil=.true. as well as </span>zeu=.true. in the input file of ph.x.  </font>and calculated the phonon modes at q=0 (gamma point).  </pre><pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">Then I have used dynmat.x. for getting </span><span style="color:black">LO-TO splitting. </span></font></pre><pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">At first, I did not added the propagation direction for q in the input file of dynmat.x .</span></font></pre><pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"> </span><span style="color:black">After running dynmat.x, it gives the following line in the output </span></font></pre><pre>……………………………………………………..</pre><pre><font face="times new roman, serif">A direction for q was not specified:TO-LO splitting will be absent</font></pre><pre>…………………………………………….</pre>

<pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">Then I specify</span><span style="color:black"> the q-point like <span></span></span></font></pre><pre><font face="times new roman, serif"><span style="color:black">q(1)=0.01, q(2)=0.0, q(3)=0.00 </span><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">in the input file of dynmat.x . </span></font></pre><pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">As a result the above line disappear from the output and the </span><span style="color:black">output is something like that<span></span></span></font></pre><pre>………………………………………………………………………………<wbr>…………………………………….</pre>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">Reading Dynamical Matrix from file dmat.gra<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     ...Force constants read<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     ...epsilon and Z* read<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     Acoustic Sum Rule: || Z*(ASR) - Z*(orig)|| =    2.089033E-02<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     Acoustic Sum Rule: ||dyn(ASR) - dyn(orig)||=    1.397683E-04<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span><font face="times new roman, serif"> </font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     Polarizability (A^3 units)<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     multiply by 0.417318 for Clausius-Mossotti correction<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">        25.389880    0.000000    0.000000<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">         0.000000   25.389880    0.000000<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">         0.000000    0.000000    1.110081<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span><font face="times new roman, serif"> </font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">     IR activities are in (D/A)^2/amu units<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span><font face="times new roman, serif"> </font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif"># mode   [cm-1]    [THz]      IR<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">    1     -0.00   -0.0000    0.0000<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">    2     -0.00   -0.0000    0.0000<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">    3     -0.00   -0.0000    0.0000<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">    4    886.97   26.5907    0.0000<span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">    5   1701.94   51.0228    0.0000</font></p><p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif">   6   1701.94   51.0228    0.0000</font></p><pre>………………………………………………………………………………<wbr>………………….</pre><pre><font face="times new roman, serif">So please tell me </font></pre><pre><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">1)  from which file </span><span style="color:black">LO-TO splitting can be found?</span><br></font></pre>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span><font face="times new roman, serif"> </font></span></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">2) How can I get </span><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">the </span>phonon dispersion with <span style="color:black">LO-TO splitting of graphene?</span><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span></span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span><font face="times new roman, serif"> </font></span></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><font face="times new roman, serif"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"> I am waiting for </span><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial">any kind suggestions. For details, I am attaching here the input files and the dispersion curve which I want to reproduce?<span></span></span></font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span><font face="times new roman, serif"> </font></span></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="times new roman, serif">Thanks in advance.<span></span></font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span><font face="times new roman, serif"> </font></span></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="times new roman, serif">Sincerely </font></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="times new roman, serif">Barnali Bhattacharya<span></span></font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="times new roman, serif">CSIR SRF, Assam University,<span></span></font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="times new roman, serif">Silchar-788011<span></span></font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="times new roman, serif">Assam, INDIA<span></span></font></span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span><font face="times new roman, serif"> </font></span></span></p>

<pre><span style="color:black"><font face="times new roman, serif"> </font></span></pre><img width="0" height="0" id="m_6934357469405981494shtracking_18s" src="https://app.saleshandy.com/web/email/countopened/4026231?userid=18781" style="display:none"></div><div></div>
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