[QE-users] hybrid fucntionals with any DFT one

[Giuseppe Mattioli]

Dear Abdeslam
In principle everything is possible, and you can build your own  
functional easily by putting together pieces of functionals already  
coded inside QE or imported through libxc (if you want to "create" a  
brand new functional you must have it hardcoded somewhere, instead),  
by defining them using the input_dft and exx_fraction variables, as  
specified into Modules/funct.f90. But given the abundance of  
functionals for all purposes, you should have a very good reason to do  
this, that you have to explain to the community if you want to publish  
work done using your own patchwork functional, and you should  
extensively test your setup before doing serious work.
HTH
Giuseppe

Quoting Abdeslam Houari via users <users at lists.quantum-espresso.org>:

> Hello,
>
> In the hybrid functionals (PBE0, HSE06 ..etc ), a part of the PBE  
> exchange (25%) is replaced by the EXX (Fock term). For example in  
> HSE06, the functional reads :
> E(HSE06)xc = 1/4E(Fock,S)x + 3/4E(PBE,S)x + E(PBE,L)x + E(PBE)c
>
> In principle, it is possible to use any DFT functional and not only  
> PBE in the formula. What about using HSE06 with PBEsol ? is it  
> possible in QE ?I can also ask why not to extend HSE06 with meta-GGA  
> (TPSS or SCAN) instead of PBE ?
>
> Best regardsAbdeslam
>
> =====================================
> Abdesalem HOUARI
> -------------------------------------------------------------------------------------------
> Department of physics, Theoretical Physics Laboratory
> University of Bejaia-06000. Algeria.
> E-mail: abdeslam.houari at univ-bejaia.dz & habdslam at yahoo.fr
> https://sites.google.com/site/houariabdeslam/homepage
> =======================================



GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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