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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman"">Dear Iurii,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman"">Thank you so much for your help! Your papers are enlightening as well.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">Please take care,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">Jacob Williams<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">PhD candidate, Yang group<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">Duke University Department of Chemistry
</span><span style="font-size:11.0pt;font-family:"CMU Bright Roman""><o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="color:black">From:
</span></b><span style="color:black">developers <developers-bounces@lists.quantum-espresso.org> on behalf of Iurii TIMROV <iurii.timrov@epfl.ch><br>
<b>Date: </b>Tuesday, May 10, 2022 at 4:15 AM<br>
<b>To: </b>developers@lists.quantum-espresso.org <developers@lists.quantum-espresso.org><br>
<b>Subject: </b>Re: [QE-developers] Static density response and xc kernels<o:p></o:p></span></p>
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<p><span style="font-size:12.0pt;color:black">Dear Jacob,<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"CMU Bright Roman";color:black">> d^2E_xc / drho(r) drho(r’)</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">This is dV_xc/drho which is the second term in Eq. 13 in PRB 88, 064301 (2013). Equations 12 and 13 of this reference are implemented in the routine LR_Modules/dv_of_drho.f90<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-family:"CMU Bright Roman";color:black">> chi(r,r’, omega=0) = drho(r)/dv(r’)</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">The response charge density drho is computed in the routine LR_Modules/incdrhoscf.f90<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">In the TDDFPT codes in QE the density-density response is computed using the Lanczos or Davidson algorithm, see e.g. Eq. 17 in the aforementioned paper. See also Eq. 3 in PRB 102, 035156 (2020).<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">HTH<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">Greetings,<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black">Iurii<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Times;color:gray">--<br>
</span><span style="font-family:"Cambria",serif;color:gray">Dr. Iurii TIMROV</span><span style="font-family:Times;color:gray"><br>
</span><span style="font-family:"Cambria",serif;color:gray">Senior Research Scientist</span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Cambria",serif;color:gray">Theory and Simulation of Materials (THEOS)</span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Cambria",serif;color:gray">Swiss Federal Institute of Technology Lausanne (EPFL</span><span style="font-family:"Cambria",serif;color:gray">)</span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Cambria",serif;color:gray">CH-1015 Lausanne, Switzerland</span><span style="font-family:Times;color:gray"><br>
</span><span style="font-family:"Cambria",serif;color:gray">+41 21 69 34 881</span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><a href="https://urldefense.com/v3/__http:/people.epfl.ch/265334__;!!OToaGQ!_7qgKZxj7LiQuYHPDWlSqP2OMFsDcVkv0JIfoBdxK5w76QTesaXPyaKXX_svTvY$"><span style="font-family:"Cambria",serif">http://people.epfl.ch/265334</span></a><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;color:black">From:</span></b><span style="font-size:11.0pt;color:black"> developers <developers-bounces@lists.quantum-espresso.org> on behalf of Jacob Williams <jacob.z.williams@duke.edu><br>
<b>Sent:</b> Monday, May 9, 2022 7:48:00 PM<br>
<b>To:</b> developers@lists.quantum-espresso.org<br>
<b>Subject:</b> [QE-developers] Static density response and xc kernels</span><span style="font-size:11.0pt">
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman"">Dear all,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman""> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman"">I am working on implementing the LOSC correction for DFT (see, e.g., arXiv:2202.01870) in QE 7.0, and am in need of calculating the zero-frequency density-density response [chi(r,r’,
omega=0) = drho(r)/dv(r’)] (or its plane-wave representation), as well as the exchange-correlation kernel [d^2E_xc / drho(r) drho(r’)]. Note that I’ve suppressed spin indices.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman""> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman"">Is this possible to do with existing routines? I know the capability must exist, because more powerful versions (the full frequency-dependent response) are used by TurboEELS
and co, but I haven’t been successful in finding how to compute the static quantities in the code. I thought the response function might be obtainable from the Kohn-Sham responses dpsi obtained from LR_Modules/response_kernels.f90, but I’m not sure how to
connect that to the full response function.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman""> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman"">Thank you in advance for your time and your help!</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman""> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">Sincerely yours,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">Jacob Williams</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">PhD candidate, Weitao Yang group</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"CMU Bright Roman";color:black">Duke University Department of Chemistry
</span><o:p></o:p></p>
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