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

Sanae Fujita sn.fjt.japan at gmail.com
Wed Mar 13 04:00:48 CET 2013


Dear WIEN2k-users,

I'm a beginner of ab-initio calculation.

I calculated MgO's DOS by WIEN2k_11.1, and DOS's graph looks well for me,

but I wonder whether my calculation works well.

Because I found message as below in scf2 file (below).

------

    QTL-B VALUE .EQ.   84.31874 in Band of energy   2.15443  ATOM=    2  L=
0

    Check for ghost bands or EIGENVALUES BELOW XX messages

    Adjust your Energy-parameters for this ATOM and L (or use -in1new
switch), check RMTs  !!!

------

I consulted User's guide(U.G.) or mails in mailing list, but I can't find
exact answer.



My question is:

(1) My process (I wrote below),in which I evaluated ghost band may consist
of eigenvalues  from EIG00014 to EIG00016, is right? Or any other good
method? Or is it true ghost band?

(2) I think that if ghost band is below Fermi energy, I can judge it is
true ghost band by checking that number of eigenvalue is equal to
NE(electron number in valence bond) in in2 file. Am I right?

(3) If (1) is 'Yes', how should I adjust energy parameter in in1 or any
other parameter?



The condition of this calculation is as below:

------

225_Fm-3m,7.96bohr cubic,

Atom1(Mg)-Pos. is (0,0,0),Atom2(O)-Pos. is (0.5,0.5,0.5),

RMT(Mg)=1.88, RMT(O)=1.88(this is the value set by w2web's RMT page, so I
think it's appropriate),

RKmax=7,Gmax=12,Emin/Emax=-9/2.5Ry,

 (4,4,4)k-points-div(in scf1, :KPT=8)

No spin-polarized calc.,

Core: Mg's 1s, O's 1s (number of electrons in semi-core and valence
band=16).

------



My process is below:

After "run_lapw -ec 0.0001 -NI "

and before "x lapw2 -qtl", I had no QTL-B message in outpput2 file.

But after "x lapw2 -qtl" to make data of DOS,

I met the  message implying ghost band in scf2 or output2 file, as cited
above.



In help032 file, I found some strange point cited below.

I think Q(UE)=84.319 in Atom2's L=0 line in the band of 2.15443eV implying
ghost band.

I don't know exact criteria of Q(UE)'s value to become ghost band,

but it's 400% of Atom2's s-like charge.

------

  BAND#  14  E=  2.15443  WEIGHT= 0.0000000

  L= 0   20.12293    1042.552    84.319  1355.684 -1110.907  -120.309

  L= 1    0.00000       0.000     0.000     0.000     0.000     0.000

  L= 2    4.42930       4.354     0.076     0.000     0.000     0.000

  D-EG:   4.42930       4.354     0.076     0.000     0.000     0.000

 D-T2G:   0.00000       0.000     0.000     0.000     0.000     0.000

  L= 3    0.00000       0.000     0.000     0.000     0.000     0.000

  L= 4    0.32295       0.322     0.001     0.000     0.000     0.000

  L= 5    0.00000       0.000     0.000     0.000     0.000     0.000

  L= 6    0.00164       0.002     0.000     0.000     0.000     0.000

------

I tried to find another evidence that BAND14 is ghost band. But I can't
find.

Dateils are below:

In scf2 or scf file, I found Fermi energy and eigenvalue of last iterarion.

-------

:FER  : F E R M I - ENERGY(TETRAH.M.)=   0.29301

------

-------

:EIG00001:      -5.0222432   -2.5763741   -2.5763741   -2.5763741
-0.9749722

:EIG00006:       0.2930142    0.2930142    0.2930142    0.6413979
1.4552772

:EIG00011:       1.4552772    1.4552772    1.7423310    1.8749247
1.8749247

:EIG00016:       2.0847470    2.0847470    2.0847470

------

I also found band14's energy range 1.77603〜2.15443 in output2.

------

band      14    1.7760284473    2.1544335535      0.000000D+00

------

So I think eigenvalue from EIG00014 to EIG00018 may belong to ghoat band.

But I can't find any strange points from these eigenvalues, because
EIG00014-EIG00018 are unoccupied states (higher than Fermi energy
0.29301Ry) as I described at my question (2).

So I wonder whether band 14 is ghost band.



Anyway, I tried to delete the "QTL-B" massage in scf2 file after "x lapw2
-qtl".

My in1_st file is cited below, I had not changed any parameters from
default setting.

-------

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    3  0      (GLOBAL E-PARAM...

 0   -1.46      0.002 CONT 1

 0    0.30      0.000 CONT 1

 1    0.30      0.000 CONT 1

K-VECTORS FROM UNIT:4   -9.0       2.5    37   emin/emax/nband

-----


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