<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-2">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Hello,</div>
<div style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
there is a bug in QE version 7.2 for exchange_only functionals in libxc, that has been fixed in the develop version.<br>
If you do not want to download the develop branch, tou just have to add the two following lines:</div>
<div style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<ul data-editing-info="{"orderedStyleType":1,"unorderedStyleType":4}">
<li style="list-style-type: "➢ ";"><span>xcoef=1.d0</span></li><li style="list-style-type: "➢ ";"><span>if (ishybrid .and. exx_started .and. exx_fraction>0.d0) xcoef=1.d0-exx_fraction</span></li></ul>
<div><span>at line 355 of XClib/xc_wrapper_gga.f90 and then recompile.</span></div>
<div><span>Cheers,</span></div>
<div><span>Fabrizio</span></div>
<div><span><br>
</span></div>
<div><span>CNR IOM<br>
</span></div>
</div>
<div style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Ayoub Aouina <ayoubaouina@outlook.com><br>
<b>Sent:</b> Thursday, August 10, 2023 9:28 PM<br>
<b>To:</b> users@lists.quantum-espresso.org <users@lists.quantum-espresso.org><br>
<b>Subject:</b> [QE-users] difference between the internal PBE and the libxc one</font>
<div> </div>
</div>
<div>
<p><font face="Dubai W23 Medium">Dear all, <br>
</font></p>
<p>I'm currently facing an issue with the use of Libxc for PBE calculations in Quantum ESPRESSO. I'm noticing a significant discrepancy in results when comparing the internal PBE functional (<code>input_dft = "PBE"</code>) to using Libxc with the PBE functional
(<code>input_dft = "XC-000I-000I-101L-130L-000I-000I"</code>).</p>
<ul>
<li>For internal PBE: Total energy contribution from xc is -4.83542517 Ry.</li><li>For Libxc PBE (<code>input_dft = "XC-000I-000I-101L-130L-000I-000I"</code>): Total energy contribution from xc is -0.63113373 Ry.</li></ul>
<p>I'm reaching out to seek insights into why such a substantial difference might occur between these calculations. I wonder if there are specific external parameters that need to be set when utilizing the PBE functional from Libxc.</p>
<p>I would also like to ask why the xc contributions are not printed in the output file for some hybrid functionals like : B3LYP?
<br>
</p>
<p>Attached is my input file and the pseudo-potential file for a Silicon calculation. Any guidance or recommendations would be highly appreciated.</p>
<p>Best regards,</p>
<pre class="x_moz-signature" cols="72">--
Ayoub Aouina, PhD.,
Institut für Festkörpertheorie und -optik
Friedrich-Schiller-Universität Jena
Max-Wien-Platz 1
07743 Jena
Germany
Mail: <a class="x_moz-txt-link-abbreviated" href="mailto:ayoub.aouina@uni-jena.de">ayoub.aouina@uni-jena.de</a></pre>
<p></p>
<p><font face="Dubai W23 Medium"></font></p>
</div>
</body>
</html>