[Wien] Ghost bands error in SrTiO3 calculation at high RKmax

[Ye Zhu]

Hi all,

I am running a calculation for SrTiO3 empty DOS using the newest version of
WIEN2k. An error I got is

           Error in LAPW2
           'l2main' - QTL-B.GT.15., Ghostbands, check scf files

which occurred during the very first round when I used RKmax = 8.  .scf2
file shows:

         QTL-B VALUE .EQ.  143.22898 in Band of energy   0.44165  ATOM=
1  L=  0
          Check for ghostbands or EIGENVALUES BELOW XX messages
          Adjust your Energy-parameters for this ATOM and L (or use -in1new
switch), check RMTs  !!!

         :WARN : QTL-B value eq. 143.23 in Band of energy   0.44165
ATOM=    1  L=  0
         :WARN : You should change the E-parameter for this atom and
L-value in case.in1 (or try the -in1new switch)

and I also found:                     Energy to separate low and high
energystates: -999.00000

Similar information is in .output2 :                   Energy to separate
semicore and valence states:  -999.000000000000

Why the energy to separate semicore and valence states cannot be found? I
have tried RKmax = 6, 7, 7.5, 8.5, 9, 10, and all went through without the
Ghostbands error. But I did see a number of warnings when RKmax > 8 :

:WAR   :             1 EIGENVALUES BELOW THE ENERGY   -9.00000
:WAR   :             1 EIGENVALUES BELOW THE ENERGY   -9.00000
:WAR   :             1 EIGENVALUES BELOW THE ENERGY   -9.00000

Is this a Emin problem? These problems at high RKmax make me worry about my
calculation. The following is my .in1 file

WFFIL  EF=.41905   (WFFIL, WFPRI, ENFIL, SUPWF)
  8.0       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT
 .23   6   0      global e-param with N other choices, napw
 0    0.200     0.000 CONT 0
 0   -2.000     0.002 CONT 0
 1    0.240     0.000 CONT 0
 1   -0.690     0.002 CONT 0
 2    0.267     0.000 CONT 1
 2    1.100     0.000 CONT 1           <<<<
 .23   6   0      global e-param with N other choices, napw
 0    0.155     0.000 CONT 0
 0   -3.800     0.002 STOP 0
 1    0.233     0.000 CONT 0
 1   -2.000     0.002 CONT 0
 2    0.200     0.000 CONT 1
 2    0.800     0.000 CONT 1         <<<<<
 .23   4   0      global e-param with N other choices, napw
 0    0.277     0.000 CONT 0
 0   -0.750     0.002 CONT 0
 1    0.268     0.000 CONT 0
 1    1.300     0.000 CONT 0        <<<<<<
K-VECTORS FROM UNIT:4   -9.0       3.0    42   emin/emax/nband #red

Most of the energies were determined using -in1new switch, and I added
high-lying local d-orbitals for Sr (atom1) and Ti (atom2), and local
p-orbital for O (atom3) (highlighted by arrows), hoping to improve the
calculation for empty DOS. The energies of these high-lying orbitals were
determined from looking at DOS plots and choosing the middle of the
interesting energy range. I increased Emax to 3.0 Ry also for the same
purpose. The following the the .in1 file right after -in1new for comparison:

WFFIL  EF=.42815   (WFFIL, WFPRI, ENFIL, SUPWF)
  9.00       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT
 .22815   5   0      global e-param with N other choices, napw
 0    0.195     0.000 CONT 0
 0   -1.976     0.000 CONT 0
 1    0.237     0.000 CONT 0
 1   -0.659     0.000 CONT 0
 2    0.267     0.000 CONT 1
 .22815   6   0      global e-param with N other choices, napw
 0    0.155     0.000 CONT 0
 0   -3.689     0.001 STOP 0
 1    0.233     0.000 CONT 0
 1   -1.961     0.000 CONT 0
 2    0.198     0.000 CONT 1
 2   -0.766     0.000 CONT 1      <<<<<
 .22815   3   0      global e-param with N other choices, napw
 0    0.277     0.000 CONT 0
 0   -0.781     0.000 CONT 0
 1    0.268     0.000 CONT 0
K-VECTORS FROM UNIT:4   -9.0       3.0    42   emin/emax/nband #red

There is one local d-orbital with -0.766 Ry for Ti which I don't quite
understand. As I care about DOS above Fermi level, I changed it to 0.8 Ry.
The volume optimization worked fine with both .in1 files, but I am always
worrying about my modifications. Please let me now if anyone knows what the
problem is or needs any more information.

Thank you very much,

Ye
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