[QE-users] XC functional

[Giuseppe Mattioli]

Dear Willem
If you look into the comments at the beginning of the file  
YourQE/Modules/funct.f90 you can see that each functional is defined  
by six parts. The first four are exchange type, correlation type,  
gradient correction to exchange type and gradient correction to  
correlation type

!              "pbe"   = "sla+pw+pbx+pbc"    = PBE

while the last two parts (when present) are reserved to embedded van  
der Waals corrections (embedded in the sense that they are not added a  
posteriori as external corrections like DFT-D2 or D3). This  
corresponds to six numbers that you can find in the output, to be sure  
that what is computed is what you expect. The same file contains also  
the meaning of all the single parts (and references to related  
papers), because you can mix-and-match with functionals (if you know  
what you are doing, of course ;-D)

HTH
Giuseppe


Quoting Offermans Willem <willem.offermans at vito.be>:

> Dear Quantum Espresso friends,
>
> I’m relatively new to QE. So sorry for a possible stupid question,  
> but what does
>
> Exchange-correlation      = SLA PW PBX PBC ( 1  4  3  4 0 0)
>
> in the output mean?
>
> The PAW data set says:
>
> H.pbe-kjpaw_psl.1.0.0.UPF
>
> So, I assumed PBE to be exchange–correlation functional.
>
>
>
> Met vriendelijke groeten,
> Mit freundlichen Grüßen,
> With kind regards,
>
>
> Willem Offermans
> Researcher Electrocatalysis SCT
> VITO NV | Boeretang 200 | 2400 Mol
> Phone:+32(0)14335263 Mobile:+32(0)492182073
>
> Willem.Offermans at Vito.be<mailto:Willem.Offermans at Vito.be>
>
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>
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GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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E-mail: <giuseppe.mattioli at ism.cnr.it>