<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Use the optimised structure with the optimised unit cell. What else? SB <br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 3 Jul 2021, at 11:01, Jibiao Li <<a href="mailto:jibiaoli@foxmail.com" class="">jibiaoli@foxmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=GB18030" class=""><pre class="">Dear All,<br class=""><br class="">I have the same concerns about phonon calculations under pressures which was posted on
<span class="date"><a href="https://www.mail-archive.com/search?l=users@lists.quantum-espresso.org&q=date:20161209" rel="nofollow" class="">Fri, 09 Dec 2016 23:33:04 </a></span><br class=""><br class="">To this end, vc-relax calculations with pressures are performed to get a compressed geometry in the beginning. However, no keywords on external pressures are required in input files of the subsequent phonon calculations. In doing so, you actually can not differentiate an optimized structure at a pressures and the unoptimized structure with the stresse. How do you know the phonon calculations are truly targeting at a compressed structure at a pressure. In my understanding, it is simply phonon calculations of an unoptimized structure with stresses. It's definitely unstable. Shall we still expect structural stability signatures from the phonon calculations of optimized structures at pressures. How do we judge stability of a structure at a pressure from phonon calculations? These questions puzzled me for a long time. Could any body help me?<br class=""><br class="">Best<br class=""></pre><div class=""><hr style="margin: 0 0 10px 0;border: 0;border-bottom:1px solid #E4E5E6;height:0;line-height:0;font-size:0;padding: 20px 0 0 0;width: 50px;" align="left" class=""><div style="font-size: 14px; font-family: Verdana;" class=""><div class=""><i class=""><font size="2" face="Times New Roman" color="#0000ff" class=""><b class="">Dr. Jibiao Li, </b></font></i></div><div class=""><i class=""><font size="2" face="Times New Roman" color="#0000ff" class=""><b class="">Department of Material Science and Engineering</b></font></i></div><div class=""><i class=""><font size="2" face="Times New Roman" color="#0000ff" class=""><b class="">Yangtze Normal University</b></font></i></div><div class=""><i class=""><font face="Times New Roman" class=""><font size="2" class=""><font color="#0000ff" class=""><b class=""><span style="text-align: left; text-transform: none; line-height: 21px; text-indent: 0px; letter-spacing: normal; font-variant: normal; text-decoration: none; word-spacing: 0px; display: inline !important; white-space: normal; orphans: 2; float: none; -webkit-text-stroke-width: 0px; background-color: transparent;" class="">Juxian Dadao 16#,</span> Fuling, Chongqing, China</b></font></font></font></i></div><div class=""><i class=""><font size="2" face="Times New Roman" color="#0000ff" class=""><b class=""><a href="mailto:jibiaoli@yznu.edu.cn" class="">Email: jibiaoli@yznu.edu.cn</a>, <a href="mailto:jibiaoli@foxmail.com" class="">jibiaoli@foxmail.com</a>, <a href="mailto:jibiao.li@hotmail.com" class="">jibiao.li@hotmail.com</a></b></font></i></div>
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<span class="Apple-style-span" style="border-collapse: separate; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; line-height: normal; orphans: 2; text-indent: 0px; widows: 2; border-spacing: 0px;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><div class=""><span class="Apple-style-span" style="border-collapse: separate; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; line-height: normal; orphans: 2; text-indent: 0px; widows: 2; border-spacing: 0px;"><span class="Apple-style-span" style="border-collapse: separate; font-variant-ligatures: normal; font-variant-position: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; line-height: normal; orphans: 2; text-indent: 0px; widows: 2; border-spacing: 0px;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><span style="font-size: 12px;" class="">— </span></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><div style="margin: 0px;" class=""><font class="Apple-style-span"><span style="font-size: 12px;" class="">Stefano Baroni - Trieste — </span><a href="http://stefano.baroni.me" style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;" class="">http://stefano.baroni.me</a><span style="font-size: 12px;" class=""> </span></font></div></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;" class=""><br class=""></div></div></div></div></div></div></div></span></span></div></div></div></span><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
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