[Pw_forum] GGA functional

[Lorenzo Paulatto]

In data 06 maggio 2009 alle ore 09:26:08, Mansoureh Pashangpour  
<mansourehp at gmail.com> ha scritto:

> Dear all
> I perform spin polarized GGA calculation for a system. I would like to  
> know the GGA functional in this calculation

Dear Mansoureh,
the functional used by the code depends on the pseudopotentials. As they  
have to be consistent with each other, just open one of them with a text  
editor and look for it, it maybe something like:
   SLA  PW   PBE  PBE    PBE  Exchange-Correlation functional
the first four fields describe the model used for exchange, correlation,  
gradient correction for the exchange and for the correlation respectively;  
the rest is the common name for it, in this case "PBE   
Exchange-Correlation functional"
There are other possible formats, though, but usually with a bit of  
imagination you can understand which functional is being used.  
Furthermore, if you've taken the pseudopotential file from the on-line  
library, the XC functional is specified in the file name, according to the  
convention explained in "Doc/nomefile.upf".


> and the order of density's partial in it.

If I understand correctly what you are asking for, it is zero (e.g. no  
derivative) for *non* gradient-corrected functionals (NOGX NOGC specified  
inside the file), and one for gradient-corrected ones. There are no  
meta-GGA pseudos, normal GGA ones are used instead.

regards

-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
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