[Pw_forum] Valence state identification

[xirainbow]

Dear Geng:
First of all,  Professor Nicola Marzari answered your question the day
before yesterday.
>The oxidation state is a phenomenological concept, and not well defined.
>The closest physical thing is the Born effective charge.
>The number of valence electrons for any pseudopotential is given
>by Z valence, in the header of that pseudopotential file.
>                       nicola

Do not continue to ask the same question. It is a wast of your time and
others!

Secondly,I do not think you can get Ba2+ or O O2-.
The valence state your mentioned is static charge.
However, static charge is not a well-defined quality, as all valence
electrons belong to the crystal, not atoms.
Maybe Mulliken charge is what you want, but I do not think QE can give it.
But QE can give Bader and Lowdin analysis, referring to
http://www.democritos.it/pipermail/pw_forum/2010-June/017204.html
http://www.democritos.it/pipermail/pw_forum/2010-May/016847.html

Alternatively, you can get dynamical charge with QE.For dynamical charge, Ba
maybe is smaller than 2 and O bigger than 2.


On Fri, Apr 1, 2011 at 11:32 AM, Liwei Geng <liweig at mtu.edu> wrote:

>  Dear all,
>
>
>
> I've done the scf calculation using atom pseudopotential files, but I can't
> know their valence state. Could you tell me how to identify the valence
> state of each ion in BaTiO3 using QE? Say, how can I know that the Ba is
> Ba2+ or O is O2-?
>
>
>
> Thanks,
>
> Liwei
>
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>


-- 
____________________________________
Hui Wang
School of physics, Fudan University, Shanghai, China
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