[Wien] EV-GGA reg

[tran at theochem.tuwien.ac.at]

More precisely, EV93 is a GGA exchange functional whose functional
derivative (i.e., the exchange potential) was fitted to exact
exchange potential. This is why it gives better band gaps than LDA or PBE:
http://iopscience.iop.org/0953-8984/19/19/196208/
The problem is that the lattice constants are very bad:
http://prb.aps.org/abstract/PRB/v50/i11/p7279_1

F. Tran

On Thu, 22 Nov 2012, Fecher, Gerhard wrote:

> and remember that it is not a total energy functional,
> it is designed for "more correct" exchange
> don't use it for structure optimization
> 
> just to prevent complaints on wrong lattice parameters when using this functional
> 
> Ciao
> Gerhard
> 
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
> 
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry
> Johannes Gutenberg - University
> 55099 Mainz
> ________________________________________
> Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at]" im Auftrag von "tran at theochem.tuwien.ac.at [tran at theochem.tuwien.ac.at]
> Gesendet: Donnerstag, 22. November 2012 14:09
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] EV-GGA reg
> 
> right
> 
> On Thu, 22 Nov 2012, yedu kondalu wrote:
> 
> > Dear Prof. F. Tran,
> >
> >   Thankyou very much for your quick reply, Initialise the calculation
> > (init_lapw) with any other exchange-correlation (xc) functional,
> > replace the xc functional by 15, then start running the calculation.
> > (If I am understand correctly).
> >
> >
> > Thanking you sir,
> >
> > Regards
> > Yedukondalu
> >
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