[Wien] in1new problem

Stefaan Cottenier Stefaan.Cottenier at fys.kuleuven.be
Mon Jun 6 13:31:49 CEST 2005


>I guess I issued this warning before: the   -in1new   switch is NOT
>necessarely more save (or better) than the default WIEN2k input. It depends
>on the case AND IN PARTICULAR how the seperation energy between semicore and
>valence is defined and found (check case.scf).
>  
>
Sure, that's what I'm very suspicious whenever I use in1new... ;-)

>The La 5d states are pretty empty, thus do not play a significant role
>for any occupied part and thus (independend on E-seper) the 4d character
>is found ONLY at the proper states leading to E-parameters for these states.
>
>However, Sb has real 5p valence states and 4p semicore! The 5p states may
>now hybridize not only for the true valnece states, but also have some
>contributions at states at eg. -1 Ry. It now depends whether these states at
>-1 Ry are found as "valence" or semicore" and of course on the amount of
>hybridization, but this admixture at eg. -1 Ry may "artificially" raise
>the 4p "semicore energy", so that it is not put at the true -6 Ry, but at
>-5.95, which is too high.
>
>Thus one must select the E-seper parameters in case.in2 properly, but 
>there may be cases, where a single "semicore/valence seperation energy
>is not sufficient and will not work.
>  
>
It is as you described, this was the reason why E-seper had to be 
increased to 0.40 Ry.

>A way out of the dilemma might be: Change write_in1 such that it
>does NOT fix the E-parameter for these low-E states, in other words, it
>should still "search" (with the original algorithm, setting a delta-E in 
>case.in1) for the E-parameter of all states below eg.  -3 Ry; 
>but set properly and automatically good
>values for the valence states. This way one would keep the original 
>settings for the deep sc states, but set proper E-parameters for the
>valence states (the "default 0.3" is the real cause of problems in most
>cases. )
>
>I include the modified (untested) script.
>Let me know, if this suggestion works.
>  
>
It produces the following case.in1 :

WFFIL        (WFPRI, SUPWF)
  7.50       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT
 .74991   7   0      global e-param with N other choices, napw
 0    0.663     0.000 CONT 1
 0   -1.254     0.000 CONT 1
 1    0.720     0.000 CONT 1
 1   -0.136     0.000 CONT 1
 2    0.838     0.000 CONT 1
 2   -5.911     0.000 CONT 1  <===========
 3    0.885     0.000 CONT 1
 .74991   6   0      global e-param with N other choices, napw
 0    0.457     0.000 CONT 1
 0   -0.212     0.000 CONT 1
 1    0.868     0.000 CONT 1
 1   -5.806     0.000 CONT 1  <==========
 2    0.883     0.000 CONT 1
 2   -1.036     0.000 CONT 1
K-VECTORS FROM UNIT:4   -9.0       3.0      emin/emax window

Compare this to the case.in1 found with the old scheme (starting from 
the case.in1 with the original in1new, at the point where it crashed) :

WFFIL        (WFPRI, SUPWF)
  7.50       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT
 .74994   7   0      global e-param with N other choices, napw
 0    0.663     0.000 CONT 1
 0   -1.254     0.005 CONT 1
 1    0.720     0.000 CONT 1
 1   -0.137     0.005 CONT 1
 2    0.838     0.000 CONT 1
 2   -5.910     0.005 CONT 1   <===========
 3    0.885     0.000 CONT 1
 .74994   6   0      global e-param with N other choices, napw
 0    0.457     0.000 CONT 1
 0   -0.213     0.001 CONT 1
 1    0.868     0.000 CONT 1
 1   -5.805     0.005 CONT 1   <========
 2    0.883     0.000 CONT 1
 2   -1.036     0.005 CONT 1
K-VECTORS FROM UNIT:4   -9.0       3.0      emin/emax window

The energies for the deep semi-core states are identical now. 
Convergence looked OK at first sight, however, there is still a QTL-B crash:

:DIS  :  CHARGE DISTANCE       0.1318234
:DIS  :  CHARGE DISTANCE       0.1646432
:DIS  :  CHARGE DISTANCE       0.1545064
:DIS  :  CHARGE DISTANCE       0.1624324
:DIS  :  CHARGE DISTANCE       0.1137017
:DIS  :  CHARGE DISTANCE       0.0394287
:DIS  :  CHARGE DISTANCE       0.0909304
:DIS  :  CHARGE DISTANCE       0.0803767
:DIS  :  CHARGE DISTANCE       0.0639179
:DIS  :  CHARGE DISTANCE       0.0504621
:DIS  :  CHARGE DISTANCE       0.0387721
:DIS  :  CHARGE DISTANCE       0.0353060
:DIS  :  CHARGE DISTANCE       0.0204696
:DIS  :  CHARGE DISTANCE       0.0127861
:DIS  :  CHARGE DISTANCE       0.0037622
:DIS  :  CHARGE DISTANCE       0.0056102

Apparantly this new write_in1 does what it should do. But the 
linearization error slowly grows, and still leads to a crash:

   QTL-B VALUE .EQ.    2.22915   in Band of energy   -5.83529
   QTL-B VALUE .EQ.    3.68742   in Band of energy   -5.81296
   QTL-B VALUE .EQ.    4.39352   in Band of energy   -5.79731
   QTL-B VALUE .EQ.    4.95376   in Band of energy   -5.78438
   QTL-B VALUE .EQ.    4.74497   in Band of energy   -5.77338
   QTL-B VALUE .EQ.    3.79768   in Band of energy   -5.76046
   QTL-B VALUE .EQ.    5.38024   in Band of energy   -5.74967
   QTL-B VALUE .EQ.    5.85567   in Band of energy   -5.74256
   QTL-B VALUE .EQ.    5.83326   in Band of energy   -5.73724
   QTL-B VALUE .EQ.    5.92836   in Band of energy   -5.73198
   QTL-B VALUE .EQ.    6.18613   in Band of energy   -5.72743
   QTL-B VALUE .EQ.    6.25986   in Band of energy   -5.72401
   QTL-B VALUE .EQ.    6.49172   in Band of energy   -5.72114
   QTL-B VALUE .EQ.    6.65410   in Band of energy   -5.71830
   QTL-B VALUE .EQ.    6.77625   in Band of energy   -5.71636
   QTL-B VALUE .EQ.    6.92212   in Band of energy   -5.71440
(and it exceeds 7.0 in the following iteration)

It looks like there is still a difference for these deep states...? The 
problematic case.struct is attached, in case you need (Rkmax=7.5, 
k-mesh=75). Symmetry is artificially reduced to tetragonal for later use.

Title
B   LATTICE,NONEQUIV.ATOMS:  2 139 I4/mmm
MODE OF CALC=RELA
  7.177134  7.177134 10.150000 90.000000 90.000000 90.000000
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT=-2
La1        NPT=  781  R0=.000010000 RMT= 2.50        Z:57.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.00000000 Y=0.00000000 Z=0.50000000
          MULT= 1          ISPLIT=-2
Sb1        NPT=  781  R0=.000010000 RMT= 2.40        Z:51.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
  16      NUMBER OF SYMMETRY OPERATIONS

Thanks,
Stefaan




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