[Wien] "X-FORCE for atom 1 is not zero as required by symmetry"

foyevtsova at th.physik.uni-frankfurt.de foyevtsova at th.physik.uni-frankfurt.de
Wed Apr 23 01:43:56 CEST 2014


Hi,

I want to calculate forces and eventually optimize internal parameters for
SrBiO3 with a unit cell of the 4_P21/n space group. Below I copy the
struct file:

str
P                            6 4_P21/n
             RELA
 11.160207 11.599001 16.096181 90.000000 90.000000 90.000000
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.25000000
          MULT= 4          ISPLIT= 2
      -1: X=0.00000000 Y=0.00000000 Z=0.75000000
      -1: X=0.50000000 Y=0.50000000 Z=0.25000000
      -1: X=0.50000000 Y=0.50000000 Z=0.75000000
Sr         NPT=  781  R0=0.00001000 RMT=    2.3500   Z:  38.00000
                     1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.50000000 Y=0.00000000 Z=0.00000000
          MULT= 2          ISPLIT= 8
      -2: X=0.00000000 Y=0.50000000 Z=0.50000000
Bi         NPT=  781  R0=0.00000500 RMT=    2.0500   Z:  83.00000
                     0.7071068 0.7071068 0.0000000
                    -0.7071068 0.7071068 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -3: X=0.50000000 Y=0.00000000 Z=0.50000000
          MULT= 2          ISPLIT= 8
      -3: X=0.00000000 Y=0.50000000 Z=0.00000000
Bi         NPT=  781  R0=0.00000500 RMT=    2.0500   Z:  83.00000
                     0.7071068 0.7071068 0.0000000
                    -0.7071068 0.7071068 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -4: X=0.09988080 Y=0.48071300 Z=0.23264600
          MULT= 4          ISPLIT= 8
      -4: X=0.90011920 Y=0.51928700 Z=0.76735400
      -4: X=0.40011920 Y=0.98071300 Z=0.26735400
      -4: X=0.59988080 Y=0.01928700 Z=0.73264600
O          NPT=  781  R0=0.00010000 RMT=    1.7000   Z:   8.00000
                     0.7071068 0.7071068 0.0000000
                    -0.7071068 0.7071068 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -5: X=0.71614580 Y=0.31476100 Z=0.05060980
          MULT= 4          ISPLIT= 8
      -5: X=0.28385420 Y=0.68523900 Z=0.94939020
      -5: X=0.78385420 Y=0.81476100 Z=0.44939020
      -5: X=0.21614580 Y=0.18523900 Z=0.55060980
O          NPT=  781  R0=0.00010000 RMT=    1.7000   Z:   8.00000
                     0.0000000-0.7071068 0.7071068
                     0.0000000 0.7071068 0.7071068
                    -1.0000000 0.0000000 0.0000000
ATOM  -6: X=0.18004640 Y=0.21865880 Z=0.95072900
          MULT= 4          ISPLIT= 8
      -6: X=0.81995360 Y=0.78134120 Z=0.04927100
      -6: X=0.31995360 Y=0.71865880 Z=0.54927100
      -6: X=0.68004640 Y=0.28134120 Z=0.45072900
O          NPT=  781  R0=0.00010000 RMT=    1.7000   Z:   8.00000
                     0.0000000 0.7071068-0.7071068
                     0.0000000 0.7071068 0.7071068
                     1.0000000 0.0000000 0.0000000
   4      NUMBER OF SYMMETRY OPERATIONS
-1 0 0 0.00000000
 0-1 0 0.00000000
 0 0-1 0.00000000
       1
 1 0 0 0.00000000
 0 1 0 0.00000000
 0 0 1 0.00000000
       2
-1 0 0 0.50000000
 0 1 0 0.50000000
 0 0-1 0.50000000
       3
 1 0 0 0.50000000
 0-1 0 0.50000000
 0 0 1 0.50000000
       4

After 'run_lapw -f 1' I get the following information in the .scf:

:WARN  : X-FORCE for atom   1 is not zero as required by symmetry:   28.2338
:WARN  : Y-FORCE for atom   1 is not zero as required by symmetry: -113.3722
:WARN  : Z-FORCE for atom   1 is not zero as required by symmetry:   11.9520
:WARN  : X-FORCE for atom   4 is not zero as required by symmetry:  -35.0616
:WARN  : Y-FORCE for atom   4 is not zero as required by symmetry:   -7.5757
:WARN  : X-FORCE for atom   5 is not zero as required by symmetry:   30.2203
:WARN  : Y-FORCE for atom   5 is not zero as required by symmetry:  -25.6543
:WARN  : X-FORCE for atom   6 is not zero as required by symmetry:   30.6085
:WARN  : Y-FORCE for atom   6 is not zero as required by symmetry:   34.8658

:ENE  : *WARNING** TOTAL ENERGY IN Ry =      -199762.69661481

       TOTAL FORCE IN mRy/a.u. = |F|     Fx             Fy             Fz 
   with/without FOR in case.in2
:FOR001:   1.ATOM     117.444686       0.000000       0.000000      
0.000000 total forces
:FOR002:   2.ATOM       0.000000       0.000000       0.000000      
0.000000 total forces
:FOR003:   3.ATOM       0.000000       0.000000       0.000000      
0.000000 total forces
:FOR004:   4.ATOM      54.932586       0.000000       0.000000     
41.603856 total forces
:FOR005:   5.ATOM      58.546663       0.000000       0.000000    
-43.084779 total forces
:FOR006:   6.ATOM      61.573155       0.000000       0.000000    
-40.481491 total forces
       TOTAL FORCE WITH RESPECT TO GLOBAL CARTESIAN COORDINATES:
:FCA001:   1.ATOM                      0.000000       0.000000      
0.000000 total forces
:FCA002:   2.ATOM                      0.000000       0.000000      
0.000000 total forces
:FCA003:   3.ATOM                      0.000000       0.000000      
0.000000 total forces
:FCA004:   4.ATOM                      0.000000       0.000000     
41.603856 total forces
:FCA005:   5.ATOM                    -30.465539     -30.465539      
0.000000 total forces
:FCA006:   6.ATOM                     28.624737     -28.624737      
0.000000 total forces
       TOTAL FORCE WITH RESPECT TO THE GLOBAL COORDINATE SYSTEM:
:FGL001:   1.ATOM                 0.000000000     0.000000000    
0.000000000 total forces
:FGL002:   2.ATOM                 0.000000000     0.000000000    
0.000000000 total forces
:FGL003:   3.ATOM                 0.000000000     0.000000000    
0.000000000 total forces
:FGL004:   4.ATOM                 0.000000000     0.000000000   
41.603856263 total forces
:FGL005:   5.ATOM               -30.465539468   -30.465539468    
0.000000000 total forces
:FGL006:   6.ATOM                28.624736882   -28.624736882    
0.000000000 total forces

For the total force, atom 1, |F|=117 whereas Fx, Fy, Fz are zeros. I need
now to optimize the x, y and z for this atom 1 but, apparently, wien2k is
using Fx, Fy, Fz as a reference and would stop immediately since these are
nominally zero.

Please, advise me on how to do optimization for atom 1 in this case.

Thanks,
Kateryna Foyevtsova



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