[Wien] QTL-B message in scf2 after "x lapw2 -qtl"

[Sanae Fujita]

Dear Prof.Blaha: Thank you very much for your kind answer to my question
about details.

I must say, about most interested energy range(for me)  0-2Ry from Fermi
level, I could get rid of ghost band by your first advise. But I want to
get rid of as higher range as possible... So please let me continue.



I tried your suggestion in your last mail and met oscillating behavior like
this:

 "After getting rid of atom2 l=1 ghost band, I got atom1 l=1 ghost band
.After getting  rid of atom1 l=1 ghost band, I got atom2 l=0 ghost band.
After getting rid of atom2 l=0 ghost band, I got atom2 l~1 ghost band...".



Is  there  further strategy to get rid of ghost band from 0-3Ry?

Adding APW+lo and LOCAL ORBITAL of l=3,4 is no sense?



Datails are below:

(I had to set emax as 3.5 ,not 2.5. But even when I set emax=3.5, situation
doesn't change.)

At first I changed atom2 l=0's LO energy parameter to 2.5Ry as below.

-----

WFFIL  EF= 0.50000       (WFFIL, WFPRI, ENFIL, SUPWF)

  7.00       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT

  0.30    4  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
APW/LAPW)

 0    0.30      0.000 CONT 1

 0   -5.57      0.001 STOP 1

 1    0.30      0.000 CONT 1

 1   -3.12      0.001 STOP 1

  0.30    4  0      (G...)

 0   -1.46      0.002 CONT 1

 0    0.30      0.000 CONT 1

 1    0.30      0.000 CONT 1

 1    2.50      0.000 CONT 1

K-VECTORS FROM UNIT:4   -9.0       2.5    18   emin/emax/nband #red

-----

But after DOS,I got QTL-B value=7.55419 in 2.07915Ry of atom1,l=1.

Next I changed atom2 l=0's LO energy parameter to 3.0Ry or 4.0Ry.

But the result was almost same.



So next, I changed atom1 l=0 energy parameter from (0.3 and -3.12)
to(2.0&-3.12).

After DOS,I got  QTL-B value=3.26254 in 2.39181Ry of atom2 l=0.

I thought this QTL-B value is rather small, so checked help032 file and
found below;

----

  L= 0   12.72219       9.975     3.263    46.972   -14.698    -9.046

----

3.263/12.72=26% is larger than a few percent, so it may not be good.

(I saw )



So next, I changed atom2 l=0 energy parameter from(-1.46&1.3)to(-1.46&2.3).

The in1_st file at this point is as below.

---

WFFIL  EF= 0.50000       (WFFIL, WFPRI, ENFIL, SUPWF)

  7.00       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT

  0.30    4  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
APW/LAPW)

 0    0.30      0.000 CONT 1

 0   -5.57      0.001 STOP 1

 1    2.00      0.000 CONT 1

 1   -3.12      0.001 STOP 1

  0.30    4  0      (GLOBAL...)

 0   -1.46      0.002 CONT 1

 0    2.30      0.000 CONT 1

 1    0.30      0.000 CONT 1

 1    2.50      0.000 CONT 1

K-VECTORS FROM UNIT:4   -9.0       2.5    18   emin/emax/nband #red

---

After DOS, I got  QTL-B value=2.94021 in 1.22167Ry of atom2 l=1 and found
below in help032 file.

---

  L= 1   47.80363      28.378     2.940     2.635     4.587     2.339

---

2.94/47.80=6.2% is still a few percent but below 10%.

User Guide says " The few percent message (e.g up to 10 %) does not
indicate a ghost band, but can

happen e.g. in narrow d-bands, where the linearization reaches its limits.
In these cases

one can add a local orbital to improve the flexibility of the basis set."

But I have already added local orbital at atom2 l=0.



I changed atom2 l=1 energy parameter from(0.3 &2.5) to (0.3,1.5).

But I got QTL-B value=10.05510 in 2.48523Ry of atom2 l=1.

I think some oscillating behavior occurred.



Best regards,

S.Fujita
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