Dear Peter,

If I remember correctly, this problem happens for point group T or Th.
I found this problem several years ago, but I have forgotten it by now.
There was a bug in assignment of class for 3-fold rotations.

Best Regards,
Koichi Kitahara
--
The University of Tokyo, Japan


On Tue, Sep 20, 2016 at 2:41 PM, Fecher, Gerhard <fec...@uni-mainz.de> wrote:
> Dear Peter,
> I tested recently and found that irrep fails mostly (>99%) for magnetic 
> systems with spin-orbit interaction
> (easyiest test cases are simple bcc iron, or fcc nickel)
> it seems it does not correctly detect the magnetic symmetries, I have 
> actually not enough time for more tests, unfortunately.
>
> 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
> and
> Max Planck Institute for Chemical Physics of Solids
> 01187 Dresden
> ________________________________________
> Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Peter 
> Blaha [pbl...@theochem.tuwien.ac.at]
> Gesendet: Dienstag, 20. September 2016 10:34
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] irrep error for symmorphic space group
>
> As far as I know it happens quite often (but not always) that irrep
> fails for spin-orbit calculations.
>
> I'm pretty sure that SO symmetry has not been implemented fully into
> irrep and this might be the reason for this.
>
> Since irrep is a contributed package by Clas Persson, I cannot help you
> much in this respect. All I can offer: Please send me the corresponding
> struct files and I will collect them as "test cases" when I find
> somebody to look in detail into this problem. But I'm not too
> optimistic, since it requires quite some knowledge and lots of work, but
> gives little "credit".
>
> Regards
>
> On 09/19/2016 04:31 PM, Kefeng Wang wrote:
>> Dear wien2k users and developers,
>>
>>
>>
>> I tried to use irrep to analysis the parity of bands. But I got error
>> saying “trsym:cannot find class” and the outputirso file is following:
>>
>>
>>
>> ********************************************************************************
>>
>>
>>
>>
>>
>> knum =  1    kname= GAMMA
>>
>> k = 0.000000 0.000000 0.000000
>>
>>
>>
>>        The point group is Th
>>
>>        24 symmetry operations in  8 classes
>>
>>        Table 79   on page  86 in Koster  et al [7]
>>
>>        Table 72.4 on page 633 in Altmann et al [8]
>>
>>
>>
>>                    E   3C2   4C3   4C3-    I  3IC2  4IC3
>> 4IC3-
>>
>>        G1+   Ag    1     1     1     1     1     1     1     1
>>
>>        G2+  1Eg    1     1     e     e*    1     1     e     e*
>>
>>        G3+  2Eg    1     1     e*    e     1     1     e*    e
>>
>>        G4+   Tg    3    -1     0     0     3    -1     0     0
>>
>>        G1-   Au    1     1     1     1    -1    -1    -1    -1
>>
>>        G2-  1Eu    1     1     e     e*   -1    -1    -e    -e*
>>
>>        G3-  2Eu    1     1     e*    e    -1    -1    -e*   -e
>>
>>        G4-   Tu    3    -1     0     0    -3     1     0     0
>>
>>        --------------------------------------------------------
>>
>>        G5+   E1/2g 2     0     1     1     2     0     1     1
>>
>>        G6+  1F3/2g 2     0     e     e*    2     0     e     e*
>>
>>        G7+  2F3/2g 2     0     e*    e     2     0     e*    e
>>
>>        G5-   E1/2u 2     0     1     1    -2     0    -1    -1
>>
>>        G6-  1F3/2u 2     0     e     e*   -2     0    -e    -e*
>>
>>        G7-  2F3/2u 2     0     e*    e    -2     0    -e*   -e
>>
>>        e=exp(2pi*i/3)
>>
>>
>>
>>        labeling of IRs can change due to choice of
>>
>>        symmetry axes: G2 <;->; G3 and G6 <;->; G7
>>
>>
>>
>>
>>
>> class, symmetry ops, exp(-i*k*taui)
>>
>>    E   21                       (+1.00+0.00i)
>>
>> 3C2    1 13 18                 (+1.00+0.00i)
>>
>> 4C3    2  3 14 15 16 17 19 20  (+1.00+0.00i)
>> (+1.00+0.00i)
>>
>>    I    4                       (+1.00+0.00i)
>>
>> 3IC2    7 12 24                 (+1.00+0.00i)
>>
>> 4IC3    5  6  8  9 10 11 22 23  (+1.00+0.00i)
>> (+1.00+0.00i)
>>
>>
>>
>> bnd ndg  eigval     E         3C2         4C3   trsym:cannot find class
>>
>>
>>
>>
>>
>> I went through the archive, and found this usually happens in the case
>> of the k point in the BZ surface of nonsymmorphic space group. But my
>> structure have 204 Im-3 space group and is symmorphic as indicated by x
>> symmetry. Also I was trying to analysis the GAMMA point which is the
>> center of BZ. But I do found that the k point which is not special point
>> works well with irrep. Another point is there are several exponential in
>> the table above instead of simple value. Could anyone tell me what’s the
>> reason of this error?
>>
>>
>>
>> Thanks a lot for your effort in advance.
>>
>>
>>
>> Best
>>
>> Kefeng Wang
>>
>>
>>
>> _______________________________________________
>> Wien mailing list
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>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>
> --
>
>                                        P.Blaha
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
> Email: bl...@theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
> WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
> --------------------------------------------------------------------------
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