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

Gavin Abo gsabo at crimson.ua.edu
Wed Apr 23 19:45:09 CEST 2014


Wien2k is probably not designed to use P21/n but uses P21/c. Struct file
before change from 14 to 4 is for P21/n, P21/c, or both?
On Apr 23, 2014 11:35 AM, <foyevtsova at th.physik.uni-frankfurt.de> wrote:

> Dear Laurence, Peter and Gerhard,
>
> thanks for your comments. Some answers:
>
> 1) I am using version 13.1. Still, min_lapw has changed the space group
> number from 14 to 4, which I only noticed after Gerhard had pointed this
> out. The regular scf cycle was done with the correct space group in
> .struct and produced "X-FORCE for atom 1 is not zero as required by
> symmetry".
>
> 2) I've never touched .in2.
>
> 3) If possible, I'd like to keep this space group or, at least, the unit
> cell dimensions for further analysis.
>
> So, can I conclude that it is not possible to optimize the position of the
> first atom using this space group/unit cell dimensions because of not
> accepting the space group suggested by sgroup? Perhaps, I should try
> reducing the symmetry to P1...
>
> Bests,
> Kateryna
>
> > Possible reasons: bug in some older version and/or a mistake made in one
> > of the input files caused by a "handbook not read error".
> >
> > Note: only the Bi atoms (atoms 2 and 3, but not 1, 4, 5, 6) are in
> > positions without free parameters
> > where the forces have to be zero by symmetry.
> > Seems that in your calculation the struct file is completely wrong
> > interpreted somewhere.
> >
> > I used the structure file with Wien2k Version 11.1 and 13.1 and min_lapw
> > as well as MSR1a (13.1 only)
> > no problems or warnings appeared.
> > However, the struct file seems to be created by a min_lapw version older
> > then 13.1 (see remark on 11.1 below)
> > in line 2 of your struct the space group is 4_P21/n and has the wrong
> > space group number it should be 14 !  (bug in older versions up to ??)
> >
> > I used batch initialisation (energy separation -8.5 and rkmax = 5.0,
> > kpoints 10, the latter 2 just to be fast)
> > and ignored the warning that the space group may be P21/c instead of
> P21/n
> > (Note: if accepting the change of sgroup it was also running without
> > problems in 13.1 with MSR1a).
> > I also guess it might be better to use smaller spheres (use the struct
> > generator to do that)
> >
> > Remark on changes made by some subroutines in the first 3 lines of the
> > structure files
> > The original header is (first 3 lines of case.struct)
> > Title
> > P   LATTICE,NONEQUIV.ATOMS:  614_P21/n
> > MODE OF CALC=RELA unit=ang
> >
> > in 11.1 min_lapw changes the 2nd lin to
> > P                            6 4_P21/n
> > that is interpreted by the structure generator as
> > P   LATTICE,NONEQUIV.ATOMS:  64_P21
> > what is a different space group
> >
> >
> > in 13.1 min_lapw changes the first 4 lines to
> > Title
> > P                            614_P21/n
> >              RELA
> >  11.160207 11.599001 16.096181 90.000000 90.000000 90.000000
> >
> > and MSR1a the second line to
> > P                            6 14 P21/n
> > interesting to note in case.struct_sgroup there is a space between
> > the number of atoms and the number of the space group
> > P   LATTICE,NONEQUIV.ATOMS:  6 14 P21/n
> > this line is read correctly by the structure generator
> >
> > would be favourable if it was always like that, because two atoms in spgr
> > twentyfive result in 225
> > and similar, this confuses always when having a quick look.
> > I also wonder wether 2220 may be interpreted as 2 atoms in I-43d or as 22
> > atoms in C2221 (I did not check it) ?
> >
> > Actually I do not really know why any sub-programm with exception of
> > sgroup (only needs a change of the 2nd line of the first 3
> > but why does it change  unit=ang to unit=bohr, this is not a symmetry
> > operation ;-)
> > should change the header of the struct files ? Seems to be historically
> > based.
> >
> > Ciao
> > Gerhard
> >
> > DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> > "I think the problem, to be quite honest with you,
> > is that you have never actually known what the question is."
> >
> > ====================================
> > Dr. Gerhard H. Fecher
> > Institut of Inorganic and Analytical Chemistry
> > Johannes Gutenberg - University
> > 55099 Mainz
> > ________________________________________
> > Von: wien-bounces at zeus.theochem.tuwien.ac.at
> > [wien-bounces at zeus.theochem.tuwien.ac.at]" im Auftrag von
> > "foyevtsova at th.physik.uni-frankfurt.de
> > [foyevtsova at th.physik.uni-frankfurt.de]
> > Gesendet: Mittwoch, 23. April 2014 01:43
> > An: wien at zeus.theochem.tuwien.ac.at
> > Betreff: [Wien] "X-FORCE for atom   1 is not zero as required by
> symmetry"
> >
> > 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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>
>
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