[Wien] irrep error for symmorphic space group

[Peter Blaha]

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
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  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: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
--------------------------------------------------------------------------