[Wien] Asking for set up case.inst

[Peter Blaha]

You NEVER change the 4s occupation, but you play with the 3d occupations
and set it to the specified values. You do NOT care about the total number
of Ni electrons and of course these changes are to be made in case.inc/up/dn
and not in case.inst.


> Dear Wien2k users,
> 
>  Recently I have read the lecture note by Dr. Madsen and Dr. Novak "calculate
> the effective U in APW methods".
> 
>  There are something is unclear for me a bit. We really need your help.
> 
>  The question is about how to set up NiO.inst  for (4.5 up spin, 3 down spin)
> calculation (everthing is clear for calculation with (4.5,4) ).
> 
>  In (4.5,3) case, Ni has 7.5  3d electrons meanwhile the total number of Ni
> valance electrons is 10, Ni- 3d8_ 4s2. Is it correct that we have to set up
> the last 2.5 electron for Ni 4s? If it is so the following file is set up
> 
>  Ni (Ni 1, is considered as impurity)
> Ar 3 5
> 3, 2,2.0      P
> 3, 2,2.0      P
> 3,-3,2.5      P
> 3,-3,1.0      P ===> total 7.5 electron for Ni_ 3d
> 4,-1,1.25    N =====> max is 1?
> 4,-1,1.25    N =====> max is 1?
> 
> But I'm so afraid that I'm wrong. Or I understand wrongly about case.inst? The
> User guide page 72-73, table 6.6 show that the max occupation for kappa = -1
> is 2. But here we split them into spin up and spin down therefore the max
> occupation is 1 for each spin up/down. Am I correct?
> 
> - If not, please advice me on this.
> 
> - If it is true, could you help me to set up the NiO.inst file for the
> calculation of (4.5 spin up ,3 spin down).
> 
> The same question is for Fe2O3 (the article Europhys. Letters. 69, 777
> (2005)). Fe3+ has five 3d electrons. We don't know how to set up the case.inst
> for both calculations: (3 spin up, 2.5 spin down) and (3 spin up,1.5 spin
> down).
> 
>  The Wien2k suggested the electronic configuration for case.inst with 3d6_4s2
> (total 8 valance electrons). If we set up 5.5 or 4.5 electrons for Fe_3d and
> how about the last 2.5 and 3.5 electron?
> 
>  Please help me to clarify this puzzle. I deeply thank for your help.
> 
> Best regards,
> Khuong
> 


                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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