[Wien] Diference in EFG values

[pieper]

Hello Stefaan and Muhammad

 From the Wien2k UG, chapter 7.1 on lapw0, I take it that Wien2k 
calculates the potential, and from that the EFG, from the TOTAL electron 
density. For lapw0 explicitely including interstitials, for the 
decomposition in lapw2 (chapter 7.7) explicitely only the electron 
density in the atomic sphere. So as a reminder to Muhammad there may 
appear (minor) differences within Wien2k between the two methods.

But in my understanding both calculations in Wien2k always include core, 
semi-core, and valence electrons (within the atomic sphere)? The 
difference to VASP can then occure because that code only considers core 
states for the EFG?

Best regards,

Martin


---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 15.09.2015 13:55, schrieb Stefaan Cottenier:
>> According to my understanding, core-state with tag F are valence 
>> states.
>> AM I right? If yes then why it is taking 3P states as valence states?
>> The valence electrons for Co are 3d7, 4s2.
> 
> You use the words 'valence electrons' in the traditional 'chemical'
> way as states outside the noble gas core. In the context of the DFT,
> the term 'valence electrons' refers to all states that are not forced
> to behave as in a free atom (i.e. they allow to feel the presence of
> the surrounding crystal).
> 
> You cannot avoid to use Co-3p as valence states with wien2k, the
> numerics would break down if you didn't.
> 
> Your output shows that wien2k has Co-3s and Co-3p as valence states,
> whereas vasp considers these as core states (i.e. they will not
> contribute to the EFG in vasp). Co-3s will never contribute to the EFG
> (spherical), whereas Co-3p could (albeit not very likely).
> 
> First consider the suggestion by Peter Blaha: make sure you have
> identical XC-functionals in both codes, and inspect whether all
> magnetic moments and the DOS and band structure pictures agree for
> both codes.
> 
> If that is all right, then use the procedure to which I refered in my
> previous post to isolate the EFG contribution of Co-3p. If that is
> nearly zero, I don't know what is going on. If it would be equal to
> the vasp-wien2k difference, then you have found the origin of your
> problem.
> 
> Stefaan
> 
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