[Wien] incorrect band splitting when RLO added for a system with spatial inversion

[Peter Blaha]

Emax seems converged. This is no issue.

Yes, from my point of view the "best" calculation should be to put 5p in 
core (+ .locre if necessary) and have the 6p RLO. It seems it has a 
rather large effect.

To check my results I would:

a) Calculate the qtl's with p-1/2 p3/2 splitting (x qtl -so) and check 
that within these bands there is significant character of p1/2 or p3/2. 
(Character-plot with band structure), which varies from Gamma-X 
explaining the importance of the p1/2 RLO.

b) Do a calculation without symmetry (P1) and calculate the bands in 
different "equivalent" directions of the BZ. I'd like to see that there 
is no symmetry-bug related to the RLOs.

c) I'd also would reconfirm, that after an scf calculation with SO but 
WITHOUT RLO, and just doing the bandstructure with and without RLO 
(non-selfconsistent) one gets more or less the same change (or is it an 
scf-effect ?). In addition, is the sum of eigenvalues (case.scf2) after 
lapw2 lower with RLO (check of variational principle).

In any case, looks interesting ....

What says experiment ???

Am 21.12.2016 um 21:50 schrieb Martin Gmitra:
> Thanks for replay!
>
> Considering the RLO for 6P (0.3 Ry), it strengthen the spin-orbit
> coupling effects rather significantly, comparable to results when
> considering RLO for 5P at -8Ry, see yellow and dark red curves in the
> attached plot.
>
> Can one understand this as the orthogonality effect as you have suggested?
>
> Important observation is that dispersions with RLO for 5P in valence
> and RLO for 6P (with 5P in core) is different (yellow and dark red
> curves). Anyhow, I am getting impression from your argumentation that
> the correct practice would be to take 5P for core + .lcore and add the
> RLO for the 6P unoccupied states, right?
>
> If one considers this case (results shown by dark red curve, RLO for
> 6P) as an benchmark, results obtained when enlarging Emax up to 45 Ry
> (blue plus symbols) can be assumed as converged (compare orange, green
> and blue curves) but hardly reach the case with RLO for 6P. There is
> still a difference of about 0.1 eV.
>
> What do you think about the observed differences?
>
> Do you think is there a sense to increase the Emax even more? (How to
> get even more bands without increasing Rkmax?)
>
> Best regards,
> Martin Gmitra
> Uni Regensburg
>
>
>
> _______________________________________________
> 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@zeus.theochem.tuwien.ac.at/index.html
>

-- 
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
--------------------------------------------------------------------------