[QE-users] Symmetry Lost

[Offermans Willem]

Dear Quantum Espresso Friends,

I’m relatively new to Quantum Espresso, so please excuse my ignorance.

I have performed a series of geometry optimisations with increased accuracy. The series consists of the same system with originally S2 Symmetry (inversion center).

During the optimisations, the system loses its S2 symmetry. This is not logical to my opinion. If I put a system with S2 symmetry in and perform a geometry optimisation, how can this symmetry disappear.

Can someone point out what the reason of this might be?


The first input file is:

<snip>
&CONTROL
   tprnfor          = .true.
   pseudo_dir       = ‘./'
/
&SYSTEM
   ecutwfc          = 25
   ecutrho          = 100
   occupations      = 'smearing'
   degauss          = 1e-05
   ntyp             = 2
   nat              = 22
   ibrav            = 0
/
&ELECTRONS
   conv_thr         = 0.0001
/
&IONS
/
&CELL
/

ATOMIC_SPECIES
Pd 106.42 Pd.pbe-n-kjpaw_psl.0.2.2.UPF
O 15.999 O.pbe-n-kjpaw_psl.0.1.UPF

K_POINTS automatic
5 5 1  0 0 0

CELL_PARAMETERS angstrom
5.58600000000000 0.00000000000000 0.00000000000000
2.79300000000000 4.83761790553987 0.00000000000000
0.00000000000000 0.00000000000000 18.24379960424911

ATOMIC_POSITIONS angstrom
Pd -0.0335794144 -0.0194045402 4.5434337591
Pd 2.8214009258 -0.0184323442 4.5449980368
Pd 1.3950257690 2.4527388071 4.5453108255
Pd 4.1923282610 2.4205853877 4.6209194390
Pd 1.4011208738 0.8092502291 6.8896667876
Pd 4.1905782218 0.8048960573 6.8423310749
Pd 2.7922495046 3.2267803491 6.8425771368
Pd 5.5950417579 3.2300318834 6.8469560609
Pd 2.7967155055 1.6150488112 9.1443519061
Pd 5.5836118435 1.6172941601 9.1216875069
Pd 4.1918881565 4.0265933964 9.1221120974
Pd 6.9787844945 4.0288387452 9.0994476982
Pd 4.1804582421 2.4138556731 11.3968435434
Pd 6.9832504954 2.4171072073 11.4012224674
Pd 5.5849217782 4.8389914992 11.4014685293
Pd 8.3743791262 4.8346373274 11.3541328167
Pd 5.5831717390 3.2233021688 13.6228801653
Pd 8.3804742310 3.1911487494 13.6984887788
Pd 6.9540990742 5.6623199007 13.6988015674
Pd 9.8090794144 5.6632920967 13.7003658451
O 1.3998448637 0.8084019389 3.3512841183
O 8.3756551363 4.8354856176 14.8925154859
</snip>

In the first output file:

<snip>
...
2 Sym. Ops., with inversion, found ( 1 have fractional translation)
…
</snip>

Met vriendelijke groeten,
Mit freundlichen Grüßen,


Willem Offermans
Researcher Electrocatalysis SCT
VITO NV | Boeretang 200 | 2400 Mol
Phone:+32(0)14335263 Mobile:+32(0)492182073

Willem.Offermans at Vito.be<mailto:Willem.Offermans at Vito.be>

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