High, Abderrahmane,

If I introduce the Ni atom and I change the Z number to 27 or 26 it
still nickel because the atom is ont only Z and I change Z the number
of neutrons and protons still inchanged.

NO! Z is the NUCLEAR charge. It sets the number of electrons automatically. If you change that you have another element! Try it by entering only the chemical symbol (e.g. Ni) in the corresponding field of the w2web struct editor. Leave the field Z empty. Press 'save and continue editing'. It will have filled in the correct Z automatically. One can circumvent this automatism, but it only makes sense if you know what you do. As I said before: find out yourself, start with a text book and the UG. You might learn enough in the process to know what you are doing.

An other question: We suppose that the ionic state of NiO is a result
from the electron density , can we force this ionic state to be
Ni+3S-3 and it's yes how?

Once again: You want to create some charge distribution of your own design where atom A lost electrons from and atom B caught them in what you decide is their own shell.

This is NOT what DFT or Wien2k does!

DFT gives you a (usually very good) approximation of where the electrons actually are in space. This may (in ionic crystals) or may not (with covalent or metallic bonds) agree more or less with your ideas.

Note that the agreement depends not only on the charge distribution itself! It heavily depends on how you decide by your experimental and/or computational methods which electron belongs where. Thats where the different definitions of charges Prof. Marks pointed out come from.

And try to get your hands on a good text book on solid state physics. It will help you far more than anyone in this mailing list can in his/her free time.

Best regards

Martin Pieper

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


Am 24.08.2017 02:23, schrieb Abderrahmane Reggad:
Thank you for all for the rich discussion

If I introduce the Ni atom and I change the Z number to 27 or 26 it
still nickel because the atom is ont only Z and I change Z the number
of neutrons and protons still inchanged.As I mentionned when I have
changed Z I have observed that the total energy changes.

An other question: We suppose that the ionic state of NiO is a result
from the electron density , can we force this ionic state to be
Ni+3S-3 and it's yes how?

Best regards

2017-08-24 0:43 GMT+01:00 Abderrahmane Reggad <jazai...@gmail.com>:

Hello

The reason for my question is that I don't how does a DFT code work
and I want to know if the ionic state is a result or an assumption.

Thank you for contribution to clarify the picture.

Best regards
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