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<p>\tau_s is the atomic positions of atom s in the unit cell e_s is
the displacement of that atom (sum over repeated index was
implied.. so there is a \sum_s in front of the derivative) <br>
</p>
<p>in the DFPT scf cycle, perturbations are organized in groups of
patterns belonging to irreducible representations that are closed
under symmetry operations and therefore need to be solved together
in order to use symmetry to reduce number of kpoints used. <br>
</p>
<p>stefano<br>
</p>
<div class="moz-cite-prefix">On 12/05/25 14:27, 半城烟沙 via users
wrote:<br>
</div>
<blockquote type="cite" cite="mid:tencent_F695697906F4A89E385C3F102F3CBD606B08@qq.com">
<div>
<div style="font-family: "lucida Grande", Verdana, "Microsoft YaHei";"><font style="line-height: 30.6px;" size="4" face="Times New Roman">Dear,</font></div>
<div style="font-family: "lucida Grande", Verdana, "Microsoft YaHei";"><font style="line-height: 30.6px;" size="4" face="Times New Roman">Thank
you for your response. The <span style="color: rgb(17, 17, 17);">τ_s (r)</span><span style="color: rgb(17, 17, 17);"> of</span> (<span style="color: rgb(17, 17, 17);">∂ Vscf / </span><span style="color: rgb(17, 17, 17);">∂</span><span style="color: rgb(17, 17, 17);">τ_s (r) * e_s * exp(-iq</span><span style="color: rgb(17, 17, 17);">τ_s</span><span style="color: rgb(17, 17, 17);">)) is the atom </span><span style="color: rgb(17, 17, 17);">displacement</span><span style="color: rgb(17, 17, 17);"> in real space (</span><span style="color: rgb(17, 17, 17);">Cartesian coordinates</span><span style="color: rgb(17, 17, 17);">)， and the </span><span style="color: rgb(17, 17, 17);"> </span><span style="color: rgb(17, 17, 17);">e_s is eigenvector of
vibrational?</span></font></div>
<div style="font-family: "lucida Grande", Verdana, "Microsoft YaHei";"><span style="color: rgb(17, 17, 17);"><font style="line-height: 30.6px;" size="4" face="Times New Roman">Jiang</font></span></div>
<div style="font-family: "lucida Grande", Verdana, "Microsoft YaHei";"><font style="line-height: 30.6px;" size="4" face="Times New Roman"><span style="color: rgb(17, 17, 17);"></span></font></div>
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<div style="font-size: 12px;font-family: Arial Narrow;padding:2px 0 2px 0;">------------------ 原始邮件 ------------------</div>
<div style="font-size: 12px;background:#efefef;padding:8px;">
<div><b>发件人:</b> "Quantum ESPRESSO users Forum"
<a class="moz-txt-link-rfc2396E" href="mailto:degironc@sissa.it"><degironc@sissa.it></a>;</div>
<div><b>发送时间:</b> 2025年5月11日(星期天) 晚上11:03</div>
<div><b>收件人:</b> "users"<a class="moz-txt-link-rfc2396E" href="mailto:users@lists.quantum-espresso.org"><users@lists.quantum-espresso.org></a>;<wbr></div>
<div><b>主题:</b> Re: [QE-users] Which matrix the 'fildvscf' tag
will calcualte?</div>
</div>
<div><br>
</div>
<p>none of the two.</p>
<p>it computes (if I recall correctly) the linear variation of
the scf potential of the vibrational pattern(s) under
examination (<font size="4" face="Times New Roman"><span style="color: rgb(17, 17, 17);">∂ Vscf / </span><span style="color: rgb(17, 17, 17);">∂</span><span style="color: rgb(17, 17, 17);">τ_s (r) * e_s * exp(-iq</span></font><font size="4" face="Times New Roman"><span style="color: rgb(17, 17, 17);">τ_s</span></font><font size="4" face="Times New Roman"><span style="color: rgb(17, 17, 17);">))</span></font> on the
FFT grid. When the self consistent calculation for a given
representation is done the code moves to the next one and the
file is overwritten. <br>
</p>
<p>stefano<br>
</p>
<div class="moz-cite-prefix">On 11/05/25 12:08, 半城烟沙 via users
wrote:<br>
</div>
<blockquote type="cite" cite="mid:tencent_78EF803ECF13900B080297C7022CA0F22005@qq.com">
<div><font size="4" face="Times New Roman">Dear,</font></div>
<font size="4" face="Times New Roman">I want to now which
matrix the 'fildvscf' tag will calcualte. The <nk|<span style="color: rgb(17, 17, 17);">∂ Vscf / </span><span style="color: rgb(17, 17, 17);">∂τ |n'k+q> or </span> <nk|<span style="color: rgb(17, 17, 17);">∂ Vscf / </span><span style="color: rgb(17, 17, 17);">∂</span><span style="color: rgb(17, 17, 17);">τ</span><span style="color: rgb(17, 17, 17);"> |n'k+q> * </span>e<span style="color: rgb(17, 17, 17);"> , where </span><span style="color: rgb(17, 17, 17);">τ is atom displacement and
</span><span style="color: rgb(17, 17, 17);">e is the
eigenvector of phonon. Anyone can help me?</span><br>
</font>
<div><font size="4" face="Times New Roman">Best regards,</font></div>
<div><font size="4" face="Times New Roman">Jiang</font></div>
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<pre class="moz-quote-pre" wrap="">_______________________________________________________________________________
The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.
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Quantum ESPRESSO is supported by MaX (<a class="moz-txt-link-abbreviated" href="http://www.max-centre.eu">www.max-centre.eu</a>)
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