[Pw_forum] Get wrong symmtry
yumin qian
yuminqian at gmail.com
Sun Nov 9 14:51:05 CET 2008
Dear Prof.
I am doing LaOFeAs ground state calculation , it symmetry blongs to
p4/nmm space group , when I finish the ground state calculation , I
procced to do the phonon calculation of Gamma point , But the output file
tell me that at Gamma point the symmetry is C_4v , but it should be D_4h,
then I look at the x.save fold to find the data-file.xml I find the
symmetry operation is completely different from the D_4h , I also use the
Vasp to do the calculation and I get the D_4h symmetry operation , I check
the possible error of my in put file for SCF calculation the only possible
error is the parameter ibrav=6, and the crystal is indeed a
Tetragonal P (st) cell
where is the errror ? Or what mistake I have made , is there someone to
tell me what's the problem ? Thanks ,I am looking forward to the answer.
this is my input file for ground state SCF calculation
&control
calculation='scf'
restart_mode='from_scratch',
pseudo_dir = '~/software/espresso-4test/pseudo',
outdir='./outscf'
prefix='LaOFeAs',
wf_collect=.true.
tstress = .true.
tprnfor = .true.
/
&system
ibrav = 6, celldm(1) =7.633740 , celldm(3)=2.136,
, nat= 8, ntyp= 4,
ecutwfc = 30.0, ecutrho = 250.0
occupations='smearing', smearing='gaussian', degauss=0.02,
/
&electrons
diagonalization='david'
conv_thr = 1.0e-10
mixing_beta = 0.5
/
ATOMIC_SPECIES
La 138.9 La.pbe-nsp-van.UPF
O 16.00 O.pbe-rrkjus.UPF
Fe 55.85 Fe.pbe-sp-van.UPF
As 74.92 As.pbe-n-van.UPF
ATOMIC_POSITIONS
La 0.2500000000 0.2500000000 0.1461000000
La 0.7500000000 0.7500000000 0.8539000000
O 0.7500000000 0.2500000000 0.0000000000
O 0.2500000000 0.7500000000 0.0000000000
Fe 0.7500000000 0.2500000000 0.5000000000
Fe 0.2500000000 0.7500000000 0.5000000000
As 0.2500000000 0.2500000000 0.6369000000
As 0.7500000000 0.7500000000 0.3631000000
K_POINTS (automatic)
8 8 4 0 0 0
~
--
Sincerely Y. M. Qian
Lab.of Condensed Matter Theory and Materials Computation
Institute of Physics
Chinese Academy of Sciences
Tel: + 8610 8264 9147
E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com>
P.O.Box 603 Beijing 100190
China
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