[Pw_forum] Valence state identification

xirainbow nkxirainbow at gmail.com
Fri Apr 1 07:07:14 CEST 2011

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

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

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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