[Pw_forum] Conserving the same Wyckoff multiplicity in the input and in the output

hqtst42 hqtst42 at netc.pl
Wed Apr 12 12:03:47 CEST 2017


Hi Paolo,

Many thanks for your reply ; maybe the problem may be something
different ; I see a symmetry break from the gipaw simulation. Because of
the symmetry, I expect, for example, 4 carbons with identical chemical
shifts, yet I have 2 pairs of 2 equivalent carbon instead. For example:

-------------------------------------------------------------------------------------------

     Total NMR chemical shifts in ppm:
---------------------------------------
     (adopting the Simpson convention for anisotropy and
asymmetry)-----------
 
     Atom  1  C   pos: (  0.702166  0.334168  0.055776)  Total
sigma:         154.68
            95.6267         39.1235        -16.2688
            45.6199        165.6715       -100.3341
           -21.3569       -108.3456        202.7526

     C    1    anisotropy:    216.17    eta:   -0.2840
     C    1    sigma_11=  103.0939    axis=(  0.761900  0.370231  0.531448)
     C    1    sigma_22=   62.1589    axis=(  0.615219 -0.670233 -0.415082)
     C    1    sigma_33=  298.7979    axis=( -0.202517 -0.643208  0.738424)
 
     Atom  2  C   pos: (  0.297834  0.203502  0.675798)  Total
sigma:         154.68
            95.6267         39.1235        -16.2688
            45.6199        165.6715       -100.3341
           -21.3569       -108.3456        202.7526

     C    2    anisotropy:    216.17    eta:   -0.2840
     C    2    sigma_11=  103.0939    axis=(  0.761900  0.370231  0.531448)
     C    2    sigma_22=   62.1589    axis=(  0.615219 -0.670233 -0.415082)
     C    2    sigma_33=  298.7979    axis=( -0.202517 -0.643208  0.738424)
 
     Atom  3  C   pos: (  0.297163  0.472864  0.419799)  Total
sigma:         155.11
            95.2156         39.0348         15.4560
            45.5222        166.0586         99.6009
            19.2085        107.7438        204.0451

     C    3    anisotropy:    215.17    eta:   -0.2971
     C    3    sigma_11=  104.6936    axis=( -0.750294 -0.387720  0.535474)
     C    3    sigma_22=   62.0730    axis=( -0.631164  0.661092 -0.405696)
     C    3    sigma_33=  298.5528    axis=(  0.196701  0.642363  0.740729)
 
     Atom  4  C   pos: (  0.702837  0.064806  0.311775)  Total
sigma:         155.11
            95.2156         39.0348         15.4560
            45.5222        166.0586         99.6009
            19.2085        107.7438        204.0451

     C    4    anisotropy:    215.17    eta:   -0.2971
     C    4    sigma_11=  104.6936    axis=( -0.750294 -0.387720  0.535474)
     C    4    sigma_22=   62.0730    axis=( -0.631164  0.661092 -0.405696)
     C    4    sigma_33=  298.5528    axis=(  0.196701  0.642363  0.740729)

-------------------------------------------------------------------------------------------

There is apparently no version number for
GIPAW:

-------------------------------------------------------------------------------------------
     Program QE v.6.0 (svn rev. 13079) starts on 16Mar2017 at 19:27:28
     ***** This is GIPAW svn revision unknown      *****
-------------------------------------------------------------------------------------------

Many thanks again for your time.

Henri Colaux


Le 2017/04/05 à 15:31, Paolo Giannozzi a écrit :
> This is what you get:
>       2 Sym. Ops., with inversion, found
>           (note:  2 additional sym.ops. were found but ignored
>            their fractional translations are incommensurate with FFT grid)
> and this is what you get if you specify "use_all_frac=.true.":
>       4 Sym. Ops., with inversion, found ( 2 have fractional translation)
> These are symmetry operations (visible with verbosity='high')
>                                     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     180 deg rotation - cart. axis [0,0,1]
>
>  cryst.   s( 2) = (    -1          0          0      )    f =(  0.0000000 )
>                   (     0         -1          0      )       (  0.5000000 )
>                   (     0          0          1      )       (  0.5000000 )
>
>  cart.    s( 2) = ( -1.0000000  0.0000000  0.0000000 )    f =(  0.0000000 )
>                   (  0.0000000 -1.0000000  0.0000000 )       (  0.2688348 )
>                   (  0.0000000  0.0000000  1.0000000 )       (  0.3657871 )
>
>
>       isym =  3     inversion
>
>  cryst.   s( 3) = (    -1          0          0      )
>                   (     0         -1          0      )
>                   (     0          0         -1      )
>
>  cart.    s( 3) = ( -1.0000000  0.0000000  0.0000000 )
>                   (  0.0000000 -1.0000000  0.0000000 )
>                   (  0.0000000  0.0000000 -1.0000000 )
>
>
>       isym =  4     inv. 180 deg rotation - cart. axis [0,0,1]
>
>  cryst.   s( 4) = (     1          0          0      )    f =(  0.0000000 )
>                   (     0          1          0      )       (  0.5000000 )
>                   (     0          0         -1      )       (  0.5000000 )
>
>  cart.    s( 4) = (  1.0000000  0.0000000  0.0000000 )    f =(  0.0000000 )
>                   (  0.0000000  1.0000000  0.0000000 )       (  0.2688348 )
>                   (  0.0000000  0.0000000 -1.0000000 )       (  0.3657871 )
>
>
>      point group C_2h (2/m)
>      there are  4 classes
>      the character table:
>
>        E     C2    i     s_h
> A_g    1.00  1.00  1.00  1.00
> B_g    1.00 -1.00  1.00 -1.00
> A_u    1.00  1.00 -1.00 -1.00
> B_u    1.00 -1.00 -1.00  1.00
>
>      the symmetry operations in each class and the name of the first element:
>
>      E        1
>           identity
>      C2       2
>           180 deg rotation - cart. axis [0,0,1]
>      i        3
>           inversion
>      s_h      4
>           inv. 180 deg rotation - cart. axis [0,0,1]
>
> On Wed, Apr 5, 2017 at 7:51 AM, Paolo Giannozzi <p.giannozzi at gmail.com> wrote:
>> Structural optimization doesn't break the symmetry. The final symmetry
>> - the one found by the code, I mean - should be  the same as the
>> initial one.
>>
>> On Wed, Apr 5, 2017 at 2:46 AM, hqtst42 <hqtst42 at netc.pl> wrote:
>>> In the input file, there are the atomic coordinates for only one
>>> molecule, and with the symmetry operation, I expect 4 equivalent
>>> molecules per unit cell. Yet, the structure optimisation results in 2
>>> pairs of 2 equivalent molecules per unit cell. I would like to explain
>>> to the program not to break the symmetry.
>>>
>>> Le 2017/04/04 à 21:45, Paolo Giannozzi a écrit :
>>>> What do you mean by "results with multiplicity 1" and "Wyckoff multiplicity?
>>>>
>>>> On Tue, Apr 4, 2017 at 12:08 PM, hqtst42 <hqtst42 at netc.pl> wrote:
>>>>> Dear everyone,
>>>>>
>>>>> In the enclosed input file, I set atomic coordinates of all equivalent atoms
>>>>> with crystal_sg and the space group.
>>>>>
>>>>> This should give results with a multiplicity of 1, but I have instead a
>>>>> multiplicity of 2 in the output file.
>>>>> How can I force the program to conserve the Wyckoff multiplicity taken as an
>>>>> input ?
>>>>> All in QE v 6.0
>>>>>
>>>>> Many thanks in advance,
>>>>>
>>>>> Henri Colaux
>>>>> Research associate
>>>>> RIKEN Yokohama
>>>>>
>>>>> _______________________________________________
>>>>> Pw_forum mailing list
>>>>> Pw_forum at pwscf.org
>>>>> http://pwscf.org/mailman/listinfo/pw_forum
>>>>
>>>
>>> _______________________________________________
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org
>>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>>
>> --
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>
>





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