[QE-users] Symmetry detection by pw.x
Paolo Giannozzi
p.giannozzi at gmail.com
Wed Mar 24 17:27:46 CET 2021
As explained more than once (MUCH more than once): a criterion is needed in
order to decide whether a rotation, or rotation+fractional translation, is
a symmetry or not. The current criterion is quite strict: approx. 5
significant digits. If you increase the parameter 'accep' in
PW/src/symm_base.f90 from 1.0e-5 from 1.0e-4, your system will have four
symmetries
Paolo
On Tue, Mar 23, 2021 at 5:57 PM Offermans Willem <willem.offermans at vito.be>
wrote:
> Dear Quantum Espresso friends,
>
> Hereafter you will find two pw.x input files: InputFile A and InputFile B.
> The files define the same system.
> The only difference is that in one of the files the atomic positions are
> translated
> to positions within the unit cell and to positions in the middle of the
> unit cell.
>
> Thereafter you will find snippets from the corresponding output files:
> OutputFile A
> and OutputFile B. The snippets show the detected symmetry by the __same__
> executable, namely:
> Program PWSCF v.6.3 starts on 23Mar2021 at 13:26:13 for A.
> Program PWSCF v.6.3 starts on 23Mar2021 at 17:37:55 for B
>
> Case A detects S_2 symmetry
> Case B detects no symmetry
>
> So translation of the structure within unit-cell changes the detected
> symmetry.
>
> Is there something I could do to seduce pw.x to find the S_2 symmetry in
> case B as well,
> besides transforming structure B back to A.
>
> If not, how can I translate the calculated “ionic+hartree potential” in
> the same way, I have
> translated A to B?
>
>
> InputFileA:
>
> <snip>
> &CONTROL
> verbosity = 'high'
> tprnfor = .true.
> forc_conv_thr = 1e-09
> pseudo_dir =
> '/scratch/antwerpen/205/vsc20500/q-e/Pt/Pt_surface_GGA_PBE_PAW/Pt221/5M3V2x1/'
> /
> &SYSTEM
> ecutwfc = 35
> ecutrho = 560
> occupations = 'smearing'
> degauss = 1e-05
> ntyp = 1
> nat = 38
> ibrav = 0
> /
> &ELECTRONS
> electron_maxstep = 200
> conv_thr = 1e-09
> mixing_beta = 0.3
> startingpot = 'atomic'
> startingwfc = 'atomic+random'
> /
> &IONS
> /
> &CELL
> /
>
> ATOMIC_SPECIES
> Pt 195.084 Pt.pbe-n-kjpaw_psl.1.0.0.UPF
>
> K_POINTS automatic
> 6 9 1 0 0 0
>
> CELL_PARAMETERS angstrom
> 5.62403200000000 0.00000000000000 0.00000000000000
> 0.00000000000000 8.43604800000000 0.00000000000000
> 0.00000000000000 0.00000000000000 21.20955287898742
>
> ATOMIC_POSITIONS angstrom
> Pt 1.4061651002 4.0599411310 -5.7765621345
> Pt 0.0001532941 1.7985387032 -5.2526504899
> Pt 4.2182087563 -0.4283346742 -4.7009783468
> Pt 0.0001642593 -2.6944921967 -4.1391134796
> Pt 1.4061214817 3.3208797727 -3.2112557851
> Pt 0.0000915723 0.9297515096 -2.5916767224
> Pt 4.2180697756 -1.4119961580 -2.0256141024
> Pt 0.0001681387 -3.6890216255 -1.3344432894
> Pt 1.4059482538 2.3757383517 -0.6457302061
> Pt 0.0000214244 0.0000043088 0.0000001310
> Pt 4.2180785861 -2.3757701390 0.6456919793
> Pt -0.0001254110 3.6890210622 1.3344441299
> Pt 1.4059592199 1.4120176059 2.0255905238
> Pt -0.0000516748 -0.9297449833 2.5916824674
> Pt 4.2179139971 -3.3208839102 3.2112850131
> Pt -0.0001088908 2.6944929715 4.1391339215
> Pt 1.4058199721 0.4283047406 4.7009005036
> Pt -0.0001689240 -1.7985466686 5.2526278998
> Pt 4.2178754128 -4.0599850729 5.7766502906
> Pt -1.4058643961 4.0599845309 -5.7766494636
> Pt 2.8121853437 1.7985474679 -5.2526244777
> Pt 1.4061986231 -0.4283048223 -4.7009008877
> Pt 2.8121251844 -2.6944951419 -4.1391305996
> Pt -1.4059029525 3.3208833141 -3.2112851898
> Pt 2.8120672554 0.9297446276 -2.5916778170
> Pt 1.4060647774 -1.4120175477 -2.0255903657
> Pt 2.8121415804 -3.6890202774 -1.3344404060
> Pt -1.4060678415 2.3757703137 -0.6456913229
> Pt 2.8119945756 -0.0000043088 -0.0000001310
> Pt 1.4060730016 -2.3757385264 0.6457295497
> Pt 2.8118476919 3.6890208407 1.3344395655
> Pt -1.4060617729 1.4119960999 2.0256139443
> Pt 2.8119248472 -0.9297511539 2.5916720720
> Pt 1.4058994737 -3.3208791766 3.2112559618
> Pt 2.8118514471 2.6944943671 4.1391101577
> Pt -1.4061953515 0.4283347559 4.7009787310
> Pt 2.8118622861 -1.7985395025 5.2526470679
> Pt 1.4058558831 -4.0599405891 5.7765613074
> </snip>
>
> InputFile B:
>
> <snip>
> &CONTROL
> verbosity = 'high'
> tprnfor = .true.
> forc_conv_thr = 1e-09
> pseudo_dir = './'
> /
> &SYSTEM
> ecutwfc = 35
> ecutrho = 560
> occupations = 'smearing'
> degauss = 1e-05
> ntyp = 1
> nat = 38
> ibrav = 0
> /
> &ELECTRONS
> electron_maxstep = 200
> conv_thr = 1e-09
> mixing_beta = 0.3
> startingpot = 'atomic'
> startingwfc = 'atomic+random'
> /
> &IONS
> /
> &CELL
> /
>
> ATOMIC_SPECIES
> Pt 195.084 Pt.pbe-n-kjpaw_psl.1.0.0.UPF
>
> K_POINTS automatic
> 6 9 1 0 0 0
>
> CELL_PARAMETERS angstrom
> 5.62403200000000 0.00000000000000 0.00000000000000
> 0.00000000000000 8.43604800000000 0.00000000000000
> 0.00000000000000 0.00000000000000 21.20955287898742
>
> ATOMIC_POSITIONS angstrom
> Pt 1.4061436758 4.0599368223 4.8282141739
> Pt 0.0001318697 1.7985343944 5.3521258185
> Pt 4.2181873319 8.0077090170 5.9037979616
> Pt 0.0001428348 5.7415514945 6.4656628288
> Pt 1.4061000572 3.3208754639 7.3935205233
> Pt 0.0000701479 0.9297472008 8.0130995860
> Pt 4.2180483511 7.0240475332 8.5791622060
> Pt 0.0001467143 4.7470220657 9.2703330190
> Pt 1.4059268293 2.3757340429 9.9590461024
> Pt 0.0000000000 0.0000000000 10.6047764395
> Pt 4.2180571617 6.0602735522 11.2504682877
> Pt 5.6238851646 3.6890167534 11.9392204383
> Pt 1.4059377955 1.4120132971 12.6303668322
> Pt 5.6239589008 7.5062987079 13.1964587759
> Pt 4.2178925726 5.1151597810 13.8160613216
> Pt 5.6239016848 2.6944886627 14.7439102300
> Pt 1.4057985477 0.4283004318 15.3056768121
> Pt 5.6238416516 6.6374970226 15.8574042082
> Pt 4.2178539884 4.3760586184 16.3814265991
> Pt 4.2181461795 4.0599802221 4.8281268449
> Pt 2.8121639193 1.7985431591 5.3521518307
> Pt 1.4061771987 8.0077388689 5.9038754207
> Pt 2.8121037600 5.7415485493 6.4656457088
> Pt 4.2181076231 3.3208790053 7.3934911186
> Pt 2.8120458310 0.9297403189 8.0130984914
> Pt 1.4060433530 7.0240261435 8.5791859428
> Pt 2.8121201560 4.7470234138 9.2703359025
> Pt 4.2179427341 2.3757660049 9.9590849856
> Pt 2.8119731512 8.4360393824 10.6047761774
> Pt 1.4060515772 6.0603051649 11.2505058581
> Pt 2.8118262675 3.6890165319 11.9392158740
> Pt 4.2179488027 1.4119917911 12.6303902528
> Pt 2.8119034227 7.5062925373 13.1964483805
> Pt 1.4058780493 5.1151645146 13.8160322703
> Pt 2.8118300227 2.6944900583 14.7438864662
> Pt 4.2178152240 0.4283304471 15.3057550394
> Pt 2.8118408617 6.6375041887 15.8574233764
> Pt 1.4058344587 4.3761031021 16.3813376159
> </snip>
>
> Symmetry found with InputFile A:
>
> <snip>
> …
> 2 Sym. Ops., with inversion, found
>
>
> s frac. trans.
>
> isym = 1 identity
>
> cryst. s( 1) = ( 1 0 0 )
> ( 0 1 0 )
> ( 0 0 1 )
>
> cart. s( 1) = ( 1.0000000 0.0000000 0.0000000 )
> ( 0.0000000 1.0000000 0.0000000 )
> ( 0.0000000 0.0000000 1.0000000 )
>
>
> isym = 2 inversion
>
> cryst. s( 2) = ( -1 0 0 )
> ( 0 -1 0 )
> ( 0 0 -1 )
>
> cart. s( 2) = ( -1.0000000 0.0000000 0.0000000 )
> ( 0.0000000 -1.0000000 0.0000000 )
> ( 0.0000000 0.0000000 -1.0000000 )
> …
> </snip>
>
> Symmetry found with InputFile B:
>
> <snip>
> …
> No symmetry found
>
>
> s frac. trans.
>
> isym = 1 identity
>
> cryst. s( 1) = ( 1 0 0 )
> ( 0 1 0 )
> ( 0 0 1 )
>
> cart. s( 1) = ( 1.0000000 0.0000000 0.0000000 )
> ( 0.0000000 1.0000000 0.0000000 )
> ( 0.0000000 0.0000000 1.0000000 )
>
> …
> </snip>
>
>
> Met vriendelijke groeten,
> Mit freundlichen Grüßen,
> With kind regards,
>
>
> Willem Offermans
> Researcher Electrocatalysis SCT
> VITO NV | Boeretang 200 | 2400 Mol
> Phone:+32(0)14335263 Mobile:+32(0)492182073
>
> Willem.Offermans at Vito.be
>
>
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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