[QE-developers] Space group does not produce correct Wyckoff positions

[박민규]

Dear all,

I found some Wyckoff positions are not correctly produced for space group I4/mmm (139) (ibrav=7).
For example, if I assign 2b and 4d Wyckoff positions, QE 6.6 produces (0,1/2,1/2) for 2b and (1/2,3/4,1/4), (1/2,1/4,3/4) for 4d.

QE 6.6 with I4/mmm (139)
2b (0,1/2,1/2)
4d (1/2,3/4,1/4)
     (1/2,1/4,3/4)

However as you can find from Bilbao Crystallographic Server<https://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list>, for I4/mmm (0,1/2,1/2) corresponds to 4c and (1/2,3/4,1/4), (1/2,1/4,3/4) correspond to 16n. According to Bilbao, 2b should be (0,0,1/2) and 4d should be (0,1/2,1/4) and (1/2,0,1/4).

Bilbao Crystallographic Server I4/mmm (139)
(0,1/2,1/2)      4c
(1/2,3/4,1/4) 16n
(1/2,1/4,3/4)

Bilbao
2b  (0,0,1/2)
4d  (0,1/2,1/4)
      (1/2,0,1/4)

So I guess there are some internal problems in the code or Bilbao is incorrect.

Best regards,
============================================
Minkyu Park
Research Institute of Basic Sciences, University of Ulsan,
93, Daehak-ro, Nam-gu, Ulsan, 44610 Republic of Korea
minkyupark at ulsan.ac.kr<mailto:minkyupark at ulsan.ac.kr>
+82-52-259-1473
============================================

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