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<p>Dear All,</p>
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<p><span style="color:rgb(33,33,33); font-family:wf_segoe-ui_normal,"Segoe UI","Segoe WP",Tahoma,Arial,sans-serif,serif,EmojiFont; font-size:15px">> (or maybe the question was on TDDFPT?)</span><br>
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<p>In TDDFPT there are already hybrids. So maybe this can be reused in DFPT for phonons? At least this could be a good starting point. Ideally, what is common between TDDFPT and DFPT should be moved to LR_Modules, which would facilitate its reuse in other linear
response codes of QE.</p>
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<p>Greetings,</p>
<p>Iurii</p>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> developers <developers-bounces@lists.quantum-espresso.org> on behalf of Nicola Marzari <nicola.marzari@epfl.ch><br>
<b>Sent:</b> Wednesday, May 6, 2020 8:06:44 PM<br>
<b>To:</b> General discussion list for Quantum ESPRESSO developers; Layla Martin-Samos<br>
<b>Subject:</b> Re: [QE-developers] Implement a functional from libxc in QE</font>
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Well, transition-metal oxides can be a good example - see the work here <br>
from the "U" gang for the phonons in CoO - major differences:<br>
<a href="https://arxiv.org/abs/1910.06195">https://arxiv.org/abs/1910.06195</a> (paper is now published in PRB).<br>
<br>
So, the question is when is EXX better than Hubbard, and one would want <br>
DFPT+EXX rather than DFPT+U (that is available)? I think for localized <br>
d/f orbitals the Hubbard approach is nicer, much less expensive, and <br>
tuned to the actual system studied.<br>
<br>
In something where self-interaciton is less well identifiable (say, an <br>
oxidized thiophene where the hole is difficult to describe), well, one <br>
could not use U and would hope that EXX helps.<br>
<br>
nicola<br>
<br>
<br>
<br>
On 06/05/2020 19:57, Layla Martin-Samos wrote:<br>
> I am not aware of any case (material, molecule, ...) in which the <br>
> vibrational spectra would have been so crappy with standard functionals <br>
> (no fock) that could justify the burden of phonons with EXX <br>
> (calculation, implementation etc...). Someone is aware of some <br>
> application of that kind? (or maybe the question was on TDDFPT?)<br>
> <br>
> Layla<br>
> <br>
> Le mer. 6 mai 2020 à 18:58, Paolo Giannozzi <p.giannozzi@gmail.com <br>
> <<a href="mailto:p.giannozzi@gmail.com">mailto:p.giannozzi@gmail.com</a>>> a écrit :<br>
> <br>
> Somebodty asked me the following question. Any comments (opther than<br>
> "it will be horribly slow")?<br>
> <br>
> > Do you know if anyone working on implementing DFPT + hybrid<br>
> functionals ?<br>
> <br>
> Paolo<br>
> <br>
> <br>
> <br>
> -- <br>
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
> Phone +39-0432-558216, fax +39-0432-558222<br>
> <br>
> _______________________________________________<br>
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> developers@lists.quantum-espresso.org<br>
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> <br>
> <br>
> _______________________________________________<br>
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> <br>
<br>
<br>
-- <br>
----------------------------------------------------------------------<br>
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL<br>
Director, National Centre for Competence in Research NCCR MARVEL, EPFL<br>
<a href="http://theossrv1.epfl.ch/Main/Contact">http://theossrv1.epfl.ch/Main/Contact</a>
<a href="http://nccr-marvel.ch/en/project">http://nccr-marvel.ch/en/project</a><br>
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