[Pw_forum] Optimizing structure problem (symmetry )

[ahmed amine]

Dear users 

i am trying to Optimize chalcopyrite structure of CuGaTe2 material 
when i run the calculation i found : No symmetry found and the atomic position has changes like 

Cu      -0.010870370   0.510130497   0.260998772
Cu      -0.016364138   0.016687430   0.014963233
Cu       0.483630499   0.516689908   0.514967544
Cu       0.489135075   0.010125472   0.760994628
Ga      -0.019121224   0.018170764   0.519353766
Ga       0.480880578   0.518172943   0.019350438
Ga      -0.022779909   0.523995568   0.773416303
Ga       0.477220624   0.023993931   0.273418499
Te       0.268656128   0.218922494   0.604739163
Te       0.765630715   0.746988837   0.610488397
Te       0.271338194   0.740863568   0.358065909
Te       0.763509887   0.224241756   0.357974497
Te       0.771337394   0.240864166   0.858066481
Te       0.265629899   0.246989419   0.110488951
Te       0.768656188   0.718922247   0.104739142
Te       0.263510461   0.724241000   0.857974279
when the first 8 atoms shoud not change



&CONTROL
  pseudo_dir = '/home/espresso/pseudo/',
  title = CuGaTe2 ,
  calculation = 'vc-relax' ,
  restart_mode = 'from_scratch' ,
  etot_conv_thr = 1.0D-5 ,
  forc_conv_thr = 1.0D-4 ,
  nstep = 200 ,
/

&SYSTEM
  ibrav=7,
  celldm(1)=11.4895348374d0, celldm(3)=1.9983552632d0,
  nat=16,
  ntyp=3,
  ecutwfc=30,
  ecutrho=160,
/

&ELECTRONS
  electron_maxstep = 200,
  mixing_beta = 0.7,
  conv_thr =  1.0d-8,
/
&IONS
  ion_dynamics = 'bfgs' ,
/
&CELL
  cell_dynamics = 'bfgs' ,
  cell_dofree = 'all' ,
/

ATOMIC_SPECIES
  Cu 63.546000   Cu_pbe_v1.2.uspp.F.UPF
  Ga 69.723000   Ge.pbe-dn-kjpaw_psl.1.0.0.UPF
  Te 127.60000   Te_pbe_v1.uspp.F.UPF

ATOMIC_POSITIONS {crystal}
  Cu   0.0000000000d0   0.5000000000d0   0.2500000000d0
  Cu   0.0000000000d0   0.0000000000d0   0.0000000000d0
  Cu   0.5000000000d0   0.5000000000d0   0.5000000000d0
  Cu   0.5000000000d0   0.0000000000d0   0.7500000000d0
  Ga   0.0000000000d0   0.0000000000d0   0.5000000000d0
  Ga   0.5000000000d0   0.5000000000d0   0.0000000000d0
  Ga   0.0000000000d0   0.5000000000d0   0.7500000000d0
  Ga   0.5000000000d0   0.0000000000d0   0.2500000000d0
  Te   0.2380000000d0   0.2500000000d0   0.6250000000d0
  Te   0.7620000000d0   0.7500000000d0   0.6250000000d0
  Te   0.2500000000d0   0.7620000000d0   0.3750000000d0
  Te   0.7500000000d0   0.2380000000d0   0.3750000000d0
  Te   0.7500000000d0   0.2620000000d0   0.8750000000d0
  Te   0.2620000000d0   0.2500000000d0   0.1250000000d0
  Te   0.7380000000d0   0.7500000000d0   0.1250000000d0
  Te   0.2500000000d0   0.7380000000d0   0.8750000000d0

K_POINTS {automatic}
 12 12 12   0 0 0
-----Ahmed amine 
phd student
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