[QE-developers] Implement a functional from libxc in QE

[Nicola Marzari]

Well, transition-metal oxides can be a good example - see the work here 
from the "U" gang for the phonons in CoO - major differences:
https://arxiv.org/abs/1910.06195 (paper is now published in PRB).

So, the question is when is EXX better than Hubbard, and one would want 
DFPT+EXX rather than DFPT+U (that is available)? I think for localized 
d/f orbitals the Hubbard approach is nicer, much less expensive, and 
tuned to the actual system studied.

In something where self-interaciton is less well identifiable (say, an 
oxidized thiophene where the hole is difficult to describe), well, one 
could not use U and would hope that EXX helps.

				nicola



On 06/05/2020 19:57, Layla Martin-Samos wrote:
> I am not aware of any case (material, molecule, ...) in which the 
> vibrational spectra would have been so crappy with standard functionals 
> (no fock) that could justify the burden of phonons with EXX 
> (calculation, implementation etc...). Someone is aware of some 
> application of that kind? (or maybe the question was on TDDFPT?)
> 
> Layla
> 
> Le mer. 6 mai 2020 à 18:58, Paolo Giannozzi <p.giannozzi at gmail.com 
> <mailto:p.giannozzi at gmail.com>> a écrit :
> 
>     Somebodty asked me the following question. Any comments (opther than
>     "it will be horribly slow")?
> 
>      > Do you know if anyone working on implementing DFPT + hybrid
>     functionals ?
> 
>     Paolo
> 
> 
> 
>     -- 
>     Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>     Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>     Phone +39-0432-558216, fax +39-0432-558222
> 
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project