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

Laurence Marks L-marks at northwestern.edu
Wed Apr 23 02:29:42 CEST 2014


Many things:

1. It appears that you did not adopt Wien2k's recommendation about
reducing to the primitive cell -- why not?
2. Your RMT's look strange. You probably need to reduce the O a bit
and increase the Bi.
3. Did you use the default case.in2? In a quick check this seems to
have forces for the first atom.
4. Are you using a new or old version?

On Tue, Apr 22, 2014 at 6:43 PM, foyevtsova at th.physik.uni-frankfurt.de
<foyevtsova at th.physik.uni-frankfurt.de> wrote:
> 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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-- 
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi


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