<div><br>Dear Prof.</div>
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<div> 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 </div>
<div>Tetragonal P (st) cell </div>
<div> 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.</div>
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<div>this is my input file for ground state SCF calculation </div>
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<div> &control<br> calculation='scf'<br> restart_mode='from_scratch',<br> pseudo_dir = '~/software/espresso-4test/pseudo',<br> outdir='./outscf'<br> prefix='LaOFeAs',<br>
wf_collect=.true.<br> tstress = .true.<br> tprnfor = .true.<br> /<br> &system<br> ibrav = 6, celldm(1) =7.633740 , celldm(3)=2.136,<br> , nat= 8, ntyp= 4,<br> ecutwfc = 30.0, ecutrho = 250.0<br> occupations='smearing', smearing='gaussian', degauss=0.02,<br>
/<br> &electrons<br> diagonalization='david'<br> conv_thr = 1.0e-10<br> mixing_beta = 0.5<br> /<br>ATOMIC_SPECIES<br>La 138.9 La.pbe-nsp-van.UPF<br>O 16.00 O.pbe-rrkjus.UPF<br>Fe 55.85 Fe.pbe-sp-van.UPF<br>
As 74.92 As.pbe-n-van.UPF<br>ATOMIC_POSITIONS<br>La 0.2500000000 0.2500000000 0.1461000000<br>La 0.7500000000 0.7500000000 0.8539000000<br>O 0.7500000000 0.2500000000 0.0000000000<br>O 0.2500000000 0.7500000000 0.0000000000<br>
Fe 0.7500000000 0.2500000000 0.5000000000<br>Fe 0.2500000000 0.7500000000 0.5000000000<br>As 0.2500000000 0.2500000000 0.6369000000<br>As 0.7500000000 0.7500000000 0.3631000000<br>K_POINTS (automatic)<br>
8 8 4 0 0 0<br>~ <br clear="all"><br>-- <br>Sincerely Y. M. Qian <br>Lab.of Condensed Matter Theory and Materials Computation <br>Institute of Physics <br>Chinese Academy of Sciences<br>
Tel: + 8610 8264 9147<br><a href="mailto:E-Mail%3Ayuminqian@gmail.com">E-Mail:yuminqian@gmail.com</a> <br>P.O.Box 603 Beijing 100190<br>China <br><br></div>