[Wien] open shell case [Si and Ge]

[Stefaan Cottenier]

Hello Gerhard,

I'm reasoning by analogy now, not by deep understanding, but indeed, if you would apply Hund's rule to the relativistic p-shell, it looks to me it would be as you describe. The p-1/2 would then play the same role as an s-orbital for Hund's rules.

Anyway, this is not relevant for wien2k free atom calculations because (1) Si and Ge are too light for the fully relativistic quantum numbers to apply, and (2) the calculations are done at the scalar-relativistic level.

Best,
Stefaan


> -----Oorspronkelijk bericht-----
> Van: Wien [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] Namens
> Fecher, Gerhard
> Verzonden: vrijdag 3 november 2017 9:29
> Aan: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
> Onderwerp: Re: [Wien] open shell case [Si and Ge]
> 
> Dear Stefaan
> What would happen if you treat all electrons relativistic, I would expect that
> the two p valence electrons occupy the p1/2,+1/2 and p1/2,-1/2 states
> leaving the 4 p3/2 states unoccupied and there would be no spinpolarisation
> 
> I did not check, maybe I am wrong.
> 
> Ciao
> Gerhard
> 
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you, is that you have never
> actually known what the question is."
> 
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry Johannes Gutenberg -
> University
> 55099 Mainz
> and
> Max Planck Institute for Chemical Physics of Solids
> 01187 Dresden
> ________________________________________
> Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von
> Stefaan Cottenier [Stefaan.Cottenier at UGent.be]
> Gesendet: Freitag, 3. November 2017 06:52
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] open shell case [Si and Ge]
> 
> Following Hund's rules, the atomic ground state for Si and Ge is spin-
> polarized ('open shell'):
> 
> https://www.webelements.com/silicon/atoms.html
> 
> Hence, yes, you need -sp to find a meaningful value for the free atom total
> energy.
> 
> Stefaan
> 
> 
> Van: Wien [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] Namens
> Gavin Abo
> Verzonden: vrijdag 3 november 2017 5:42
> Aan: wien at zeus.theochem.tuwien.ac.at
> Onderwerp: Re: [Wien] open shell case [Si and Ge]
> 
> Feel free to correct me if I'm wrong, but I think Si and Ge have an even
> number of electrons (or paired electrons).
> 
> For Si, 4 electrons in the 3s^2 3p^2.  For Ge, 4 electrons in the 4s^2 4p^2. [1]
> 
> This making them closed shell [2].
> 
> In Prof. Blaha's example for free atoms [3], spin-polarized (runsp_lapw) is
> used for open shell (or non-closed shell [4]) Li (1 electron in 2s^1) and B (3
> electron in 2s^2 2p^1) and non-spin polarized is used for closed shell Be (2
> electron in 2s^2).
> 
> I don't know why it is fluctuating, diverging?  Is the box you used containing
> the free atom large enough?  I remember that 12x12x12 angstrom usually
> might be large enough [5].
> 
> [1]
> https://en.wikipedia.org/wiki/Electron_configurations_of_the_elements_(da
> ta_page)
> [2] https://www.mail-
> archive.com/wien at zeus.theochem.tuwien.ac.at/msg11320.html
> [3] https://www.mail-
> archive.com/wien at zeus.theochem.tuwien.ac.at/msg16691.html
> [4] http://susi.theochem.tuwien.ac.at/reg_user/faq/cohesive.html
> [5] https://www.mail-
> archive.com/wien at zeus.theochem.tuwien.ac.at/msg12815.html
> On 11/2/2017 7:06 PM, chin Sabsu wrote:
> Dear Peter Sir,
> 
> Do Si [S^23P^4]  and Ge [4S^24P^2] are also an open shell case?
> 
> Because my Si atomization energy is fluctuating without -sp switch after 55
> scf cycles also.
> 
> 
> 
> Sincerely
> 
> Chin
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-
> archive.com/wien at zeus.theochem.tuwien.ac.at/index.html