[Pw_forum] electron configuration of Ni

Masoud Nahali masoudnahali at live.com
Wed Dec 15 21:57:32 CET 2010

Dear Heather and QE Users

Many thanks for your attention and answer. The case of study is a Ni
atom which is connected to 4 carbon atoms in a graphite-like
structure. The projected DOS calculation by projwfc.x (lowdin charge
analysis) after relaxation procedure
shows that the Ni electronic configuration is : 4s[0.4023] +
3d[8.8971]. As I know the initial guess of this pseudo-potential is
3d[9] 4s[1] for Ni and I wanna to know that if the initial guess
was 3d[8] 4s[2], would I get 4s[0.4023] + 3d[8.8971] again after the
relaxation procedure or not ? I appreciate any suggestion in advance.

Best Wishes


Masoud Nahali

PhD Student of Physical Chemistry
Sharif University of Technology

 Heather Kulik wrote :

Dear Masoud,
> You are correct in that the pseudopotential was generated in the state 3d9
> 4s1.
> One minor point is that according to NIST (
> http://physics.nist.gov/PhysRefData/ASD/levels_form.html), the low-lying
> experimental atomic energy levels of Ni are:
> ^3F(3d84s2) ~0 and ^3D(3d94s1) ~ <0.1 eV, ^1D(3d94s1) ~ <0.5 eV.
> However, the good news is that, the state in which the pseudopotential was
> generated should not prevent you from accurately describing states that
> have
> 3d84s2 character since the core electrons from a 3d94s1 and 3d84s2 Ni
> should
> be described fairly similarly.
> You can also verify the character of your electronic states using any of
> the
> postprocessing codes (e.g. projected density of states from projwfc.x)
> Note: A more serious problem is that if your extended system (i.e. more
> than
> one atom) has numerous solutions close in energy comparable to the
> character
> of the atomic system, most x-c functionals will likely fail to predict the
> correct ordering.
> You should try comparing the relative energies you get for a few
> representative systems to experimental data where possible to identify if
> the GGA (or LDA) suffers from any particular bias in the relative ordering
> of these states.
> Hope that helps!
> --
> Heather K
> Postdoc at Stanford University
> On Wed, Dec 15, 2010 at 12:31 AM, Masoud Nahali <masoudnahali at live.com<http://www.democritos.it/mailman/listinfo/pw_forum>
> >wrote:

>* Dear Quantum Espresso Users
*>* I have used Ni.pbe-nd-rrkjus.UPF pseudo-potential for nickel in my project.
*>* In the info part of this pseudopotential has been written :
*>* Info:   Ni PBE 3d9 4s1 RRKJ3 US
*>* But I know that the well established electron configuration for nickel is
*>* "3d8 4s2" and now I am too worry that it may cause an error in my work. May
*>* it ?
*>*  I appreciate your help to understand the point in advance. Many Thanks
*>* Best Wishes
*>*  *
*>* -----------------
*>* Masoud Nahali
*>* PhD Student of Physical Chemistry
*>* Sharif University of Technology
*>* *

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