[Pw_forum] Get wrong symmtry
akohlmey at cmm.chem.upenn.edu
Sun Nov 9 19:14:10 CET 2008
On Sun, 9 Nov 2008, yumin qian wrote:
YQ> Dear Prof.
YQ> I am doing LaOFeAs ground state calculation , it symmetry blongs to
YQ> p4/nmm space group , when I finish the ground state calculation , I
YQ> procced to do the phonon calculation of Gamma point , But the output file
YQ> tell me that at Gamma point the symmetry is C_4v , but it should be D_4h,
YQ> then I look at the x.save fold to find the data-file.xml I find the
YQ> symmetry operation is completely different from the D_4h , I also use the
YQ> Vasp to do the calculation and I get the D_4h symmetry operation , I check
YQ> the possible error of my in put file for SCF calculation the only possible
YQ> error is the parameter ibrav=6, and the crystal is indeed a
YQ> Tetragonal P (st) cell
YQ> where is the errror ? Or what mistake I have made , is there someone to
how about not having enough numerical accuracy
for the numbers in the z-coordinate?
YQ> tell me what's the problem ? Thanks ,I am looking forward to the answer.
YQ> this is my input file for ground state SCF calculation
YQ> pseudo_dir = '~/software/espresso-4test/pseudo',
YQ> tstress = .true.
YQ> tprnfor = .true.
YQ> ibrav = 6, celldm(1) =7.633740 , celldm(3)=2.136,
YQ> , nat= 8, ntyp= 4,
YQ> ecutwfc = 30.0, ecutrho = 250.0
YQ> occupations='smearing', smearing='gaussian', degauss=0.02,
YQ> conv_thr = 1.0e-10
YQ> mixing_beta = 0.5
YQ> La 138.9 La.pbe-nsp-van.UPF
YQ> O 16.00 O.pbe-rrkjus.UPF
YQ> Fe 55.85 Fe.pbe-sp-van.UPF
YQ> As 74.92 As.pbe-n-van.UPF
YQ> La 0.2500000000 0.2500000000 0.1461000000
YQ> La 0.7500000000 0.7500000000 0.8539000000
YQ> O 0.7500000000 0.2500000000 0.0000000000
YQ> O 0.2500000000 0.7500000000 0.0000000000
YQ> Fe 0.7500000000 0.2500000000 0.5000000000
YQ> Fe 0.2500000000 0.7500000000 0.5000000000
YQ> As 0.2500000000 0.2500000000 0.6369000000
YQ> As 0.7500000000 0.7500000000 0.3631000000
YQ> K_POINTS (automatic)
YQ> 8 8 4 0 0 0
Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu http://www.cmm.upenn.edu
Center for Molecular Modeling -- University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425
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