[Wien] How to know if the M+2 has a high spin from calculation?

[Víctor Luaña Cabal]

On Sat, Aug 26, 2017 at 12:20:19PM +0100, Abderrahmane Reggad wrote:
> Dear wien2k users
> 
> We know that the ion Fe+2 has a high spin configuration (3d6 (teg(4) eg(2))
> because the crystal field effect..
> 
> How to check that from calculation ?

Abderrahmane,

There are several questions implicit here.

1) By asking for a crystal field interpretation you are demanding the
   orbital population of a Fe(+2)L6 octahedral or tetrahedral cluster,
   because t2g and eg are the names of the O_h and T_h irreps (irreducible
   representations). You know tyhe population by examining the orbital
   energies of the irreps: the irreps with smaller energies are populated
   first. Given an open shell population symmetry lets you predict the
   total spin of the cluster, so you can check whether this agrees or
   not with the electronic state of your impurity.

2) By using a band structure code F(+2) levels contribute to a local band,
   that are labeled in the output with the indication of the irrep of
   the impurity contributing most.

Hope this helps you. Best reards,
                                 Víctor Luaña
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