[Wien] Irrep output file
Peter Blaha
pblaha at theochem.tuwien.ac.at
Mon Jun 22 09:41:48 CEST 2020
Please send me exactly the struct file you are using (with SO) + details
of the calculation (spin-polarization ???) to my private email.
Are you using the latest WIEN2k version ?
Am 21.06.2020 um 23:27 schrieb Md. Fhokrul Islam:
> Hi Gavin,
>
> Thank you for your reply. I have another calculation with a different
> k-path but output file still contains "??" marks. I am also not sure if
> the complex numbers are the characters of the point group. Here are few
> bands at a general k-points which belongs to C1 point group. This group
> has only unit operator, E. So, the character of E should be 1. But the
> numbers listed under operator E in the output file are clearly
> different, and doesn't look like due to rounding error. Maybe I
> misunderstood the output file.
>
>
> knum = 2 kname=
> k = 0.000000 0.000000 0.225000
>
> The point group is C1
> 1 symmetry operations in 1 classes
>
> E
> G1 A1 1
> --------------
> G2 A1/2 1
>
> bnd ndg eigval E
> ....
> 15 2 -4.673171 1.56-0.00i ??
> 17 2 -4.673047 0.04+0.00i ??
> 19 2 -4.673041 0.03-0.00i ??
> 21 4 -4.672125 0.07-0.00i ??
>
>
> Thanks,
> Fhokrul
> ------------------------------------------------------------------------
> *From:* Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of
> Gavin Abo <gsabo at crimson.ua.edu>
> *Sent:* Sunday, June 21, 2020 3:35 AM
> *To:* wien at zeus.theochem.tuwien.ac.at <wien at zeus.theochem.tuwien.ac.at>
> *Subject:* Re: [Wien] Irrep output file
> I'm not sure that I have the proper answers but given below is what I'm
> currently thinking they might be.
>> I am trying to extract irreducible representation of eigenvalues. I
>> have obtained the case.outputirso and case.irrepso files. But I am not
>> sure if I understood these files correctly. The Ci point group has two
>> irreducible representations as listed in the file but many of the
>> eigenstates are labelled by "??". Am I doing anything wrong?
>
> The 3.99-0.00i 0.00+0.00i for band 109 for E and I values,
> respectively, look very close to 4.00+0.00i 0.00-0.00i for band 105. I
> wondering if perhaps there is some round off error where the ?? might
> indicate that the program was not able to identify a irreducible
> representation label corresponding to 3.99-0.00i 0.00+0.00i (since it
> would need to be 4.00+0.00i 0.00-0.00 to have G2+ + G2+ + G2- + G2- in
> this case). I'm wondering if that would be effected by your k-mesh.
> Have you tried change it to see if the values change? There is also a
> tolerance value (TOL variable) in SRC_irrep/wrtir.f that looks like it
> could be adjusted. Though, I would only fiddle with that as a last resort.
>
>> The bands 105 -108 are four-fold degenerate with irrep of the double
>> group G2+, G2+,G2-,G2-, respectively, right?
>
> I believe you are right about that.
>
>> Also, can anyone please clarify what are the complex numbers under
>> operators E and I?
>
> Since in some point groups the characters can be complex [1], I guessing
> the developer for programming simplicity decided to output the results
> always in complex number notation even though in many cases it is only a
> real number. For your calculation, it appears to be only be a real
> number as the imaginary part is zero (i.e., 0.00i).
>
> [1]
> https://chem.libretexts.org/Courses/Pacific_Union_College/Quantum_Chemistry/12%3A_Group_Theory_-_The_Exploitation_of_Symmetry/12.06%3A_Character_Tables#Irreducible_representations_with_complex_characters
>
>> case. outputirso:
>>
>> The point group is Ci
>> 2 symmetry operations in 2 classes
>> Table 6 on page 32 in Koster et al [7]
>> Table 11.4 on page 138 in Altmann et al [8]
>>
>> E I
>> G1+ A1g 1 1
>> G1- A1u 1 -1
>> --------------------
>> G2+ A1/2g 1 1
>> G2- A1/2u 1 -1
>>
>>
>> class, symmetry ops, exp(-i*k*taui)
>> E 2 (+1.00 0.00i)
>> I 1 (+1.00 0.00i)
>>
>> bnd ndg eigval E I
>> 1 2 -4.675588 1.99+0.00i -1.99-0.00i ??
>> 3 2 -4.675572 1.99-0.00i 1.99-0.00i ??
>> 5 2 -4.674606 1.98-0.00i -1.98+0.00i ??
>> ...
>> ...
>> 97 4 -4.261267 3.97+0.00i -0.00-0.00i ??
>> 101 4 -4.261167 3.99-0.00i 0.01+0.00i ??
>> 105 4 -4.260795 4.00-0.00i 0.00+0.00i =G2+ + G2+ + G2- + G2-
>> 109 4 -4.259344 3.99-0.00i 0.00+0.00i ??
>> 113 4 -4.258747 4.00+0.00i 0.00-0.00i =G2+ + G2+ + G2- + G2-
>> 117 4 -4.258715 4.00-0.00i 0.00+0.00i =G2+ + G2+ + G2- + G2-
>> 121 4 -2.333313 3.90-0.00i -0.01-0.00i ??
>> 125 4 -2.333098 4.00+0.00i -0.00-0.00i =G2+ + G2+ + G2- + G2-
>> 129 4 -2.332321 3.93+0.00i -0.02+0.00i ??
>>
>> The corresponding bands in the case.irrepso file:
>> ....
>> 104 4 -4.261165 0 0 0 0 0 0 0 0
>> 105 4 -4.260795 2 1 2 1 -2 1 -2 1
>> 106 4 -4.260795 2 1 2 1 -2 1 -2 1
>> 107 4 -4.260791 2 1 2 1 -2 1 -2 1
>> 108 4 -4.260791 2 1 2 1 -2 1 -2 1
>> 109 4 -4.259344 0 0 0 0 0 0 0 0
>> 110 4 -4.259344 0 0 0 0 0 0 0 0
>> ....
>>
>> What are the numbers in column 4-7?
>
> In case. outputirso for band 105, there is:
>
> G2+ + G2+ + G2- + G2-
>
> In case.irrepso for band 105, there is:
>
> 2 1 2 1 -2 1 -2 1
>
> The columns 4 & 5, 6 & 7, 8 & 9, and 10 & 11 might correspond to
> irreducible representation numbers that correspond with the labels
> (e.g., G2+ with 2 1 and G2- with -2 1).
>
>
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--
Peter Blaha
Inst.Materials Chemistry
TU Vienna
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