WIEN2k-FAQ: QTL-B

©2001 by P. Blaha, K. Schwarz and J. Luitz


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In some cases (mostly when the spheres are extremely small or you have heavy elements) it may even happen, that during the (first or later) scf-cycle LAPW2 stops with a QTL-B error

FORTRAN STOP L2main - QTL-B Error´

To find out more about an error (in general) you should check the "error" files:

/susi/pblaha/lapw/fccpt> lse 
0 -rw-rw-r--  1 pblaha tc  0 2005-04-21 19:26 dstart.error 
0 -rw-rw-r--  1 pblaha tc  0 2005-04-21 19:26 lapw0.error 
0 -rw-rw-r--  1 pblaha tc  0 2005-04-21 19:26 lapw1.error 
4 -rw-rw-r--  1 pblaha tc 53 2005-04-21 19:26 lapw2.error 
Since lapw2.error has non-zero length:
/susi/pblaha/lapw/fccpt> cat lapw2.error
 'l2main' - QTL-B.GT.15., Ghostbands, check scf files
Since the error is in lapw2, you need to check case.scf2:
/susi/pblaha/lapw/fccpt> cat *scf2
...
:FER  : F E R M I - ENERGY(TETRAH.M.)=   1.01765
...
   QTL-B VALUE .EQ.  120.91788   in Band of energy    1.12346   ATOM=    1   L=  2
    Check for ghostbands or EIGENVALUES BELOW XX messages
    Adjust your Energy-parameters for this ATOM and L (or use -in1new switch), check RMTs  !!!
:E2_0001: E( 2)=    0.3000   E(BOTTOM)=   -0.066   E(TOP)= -200.000
:E2_0001: E( 2)=    0.0100   E(BOTTOM)=   -0.966   E(TOP)= -200.000
             APW+lo
:E2_0001: E( 2)=    0.3000
             LOCAL ORBITAL
....     part of case.in1
WFFIL  EF=0.50            (WFFIL, WFPRI, ENFIL, SUPWF)
 6       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT
  0.30    6  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
 0    0.30      0.000 CONT 1
 0   -4.30      0.001 STOP 1
 1   -2.54      0.002 CONT 1
 1    0.30      0.000 CONT 1
 2    0.01      0.001 CONT 1
 2    0.30      0.000 CONT 1
....

Peter Blaha,