The Bravais lattice for the case of unique axis 'b' should be the one corresponding to case ibrav=-13, as described in the documentation
Paolo On Tue, Dec 15, 2020 at 9:30 AM 连云龙 <lia...@ihep.ac.cn> wrote: > Dear QE experts, > > > I find it confusing in the description Wyckoff position specifications in > the card ATOMIC_POSITIONS. > > https://www.quantum-espresso.org/Doc/INPUT_PW.html > > > For space group No.12 under the convention unique axis b, there are three > cell choices. The Wyckoff position 4i has different forms for the three > choices, namely (according to ITA) > > UNIQUE AXIS b, CELL CHOICE 1 > > 4i x,0,z ; x+1/2,1/2,z ; xb,0,zb ; xb+1/2,1/2,zb > > UNIQUE AXIS b, CELL CHOICE 2 > > 4i x,0,z ; x,1/2,z+1/2 ; xb,0,zb ; xb,1/2,zb+1/2 > > UNIQUE AXIS b, CELL CHOICE 3 > > 4i x,0,z ; x+1/2,1/2,z+1/2 ; xb,0,zb ; xb+1/2,1/2,zb+1/2 > > (xb means x-bar) > > > If I am to write the ATOMIC_POSITIONS card, how should I specify the > parameters x and z? How do I know that pw.x takes CELL CHOICE 1/2/3 ? > > > Thank you for your help. > > > Best regards, > > Yunlong Lian > > -- > Yunlong LIAN ORCID : https://orcid.org/0000-0002-9474-2181 CSNS, Dongguan > Neutron Science Center Dongguan, Guangdong, P. R. China 连云龙 中国散裂中子源 中子科学部 > A1-629 (内线 303) 中国广东省东莞市 > > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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