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



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                                      P.Blaha
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