[Wien] optical property

[Peter Blaha]

> Yes, I really did as following,
> runsp_lapw
> save_lapw xx...
> runsp_lapw -orb
> continuing with the old density, NO  dstart !!!

What about the Mn moment right at the beginning when you start after
save_lapw. At least in the first iterations it should be large ?

If you think you made everything correct, test it with a very small U,J
Then the LDA+U effect should go to zero, i.e. you should come back to the
runsp solution.

> What I am curious is that the ENE changes a lot. Does it mean it goes to
> another local minimum position which is non-magnetic state? Or there should
> be a big energy difference while I choose -orb option.

Yes, there should be a big energy difference. It is another functional, and
you cannot compare energies of a GGA and LDA+U run.


> I really don't know if it is necessary to use LDA+U for Pr 4f state. That
> is my question too. Should I use it? I found in literature they only
> mentioned LDA+U for Mn for this kind of materials.

Rare earth 4f states always give problem (except for half filling), since the
4f states are pinned at EF, make everything metallic and give difficulty
in convergence.
                                      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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