[Wien] How to force a particular orbital state

[Peter Blaha]

As mentioned before, this depends on your system (elements) and symmetry.

In standard LDA/GGA calculations most of the time you cannot force a particular
occupation except by a specific (usually large) distortion.
Often one can use LDA+U to force a particular orbital state.

a) runsp -orb     # run a standard LDA+U calculation
b) Create/modify case.dmatup or dn such that you have the desired occupation
    (This needs a bit of "understanding" what dz2 or d-x2-y2 state is in an lm-basis.
     But when you compare the :QTL line with a dmat file, you should be a ble to
     figure it out correctly.
c) x orb -up; x orb -dn
d) runsp -orbc    # this should create am occupation/ density with the desired occupation.
e) save_lapw calc_with_constrained_occup
f) x lapwdm -up /-dn    create new damtup/dn files
g) runsp -orb      # check out, if this state remains stable. Sometimes it requires also
    a structural optimization.

Am 03.03.2013 13:10, schrieb Tulika Maitra:
> Dear Wien2K Users,
>
> I was interested to know if there is a possibility in Wien2k to force a particular orbital state and run the scf to calculate
> the total energy. For example, if I have one d electron in eg orbitals. Is it possible to force this electron to occupy either
> dx2-y2 or dz2 orbital and run the scf to calculate the total energy?
>
> As it is not clear from the manual or the mailing list, I would greatly appreciate if anybody can help.
>
> Thanks & regards
>
> Tulika Maitra
>
>
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-- 
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Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
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