[Pw_forum] QE creating wrong i/p file for crystal_sg option

[Muthu V]

Dear Users
I have a question regarding the usage of crystal_sg option to specify
atomic position in pw input file. I'm trying make pw i/p file for TiO2
rutile system. its space group # is 136 , Ti is at 2a  site and O is at 4e
site.so from ITA i have the following i/p data

Ti 2a (0, 0, 0) (0.5, 0.5, 0.5)
O  4e (0, 0, z) (0.5, 0.5, z+1/2) (0.5, 0.5, -z+1/2)(0,0,-z)

the z value is 0.305. so from this i have created following pw.x input file

&control
      calculation ='scf'
     restart_mode = 'from_scratch',
           prefix = 'ge'
       pseudo_dir = '/home/pearl/qe-5.4.0/pseudo/',
           outdir ='/home/pearl/qe-5.4.0/tio2/tmp/'
 /
 &system
            ibrav =  6 ,
      space_group = 136,
                A = 4.59373 ,
                C = 2.95812 ,
              nat = 2 ,
             ntyp = 2 ,
          ecutwfc = 20.0 ,
          ecutrho = 80.0 ,
      occupations = 'smearing' ,
          degauss = 0.1 ,
         smearing = 'gaussian' ,
 /
 &electrons
         conv_thr =  1.0d-8 ,
      mixing_beta = 0.7 ,
 /
ATOMIC_SPECIES
 Ti  47.867   Ti.pz-mt_fhi.UPF
 O   16.000   O.pz-mt_fhi.UPF
ATOMIC_POSITIONS crystal_sg
Ti   2a
O    4e  0.305
K_POINTS automatic
4 4 4 0 0 0

with this file i'm able to run pw.x without any error message. but the
following are my questions :

1) the atomic position written in output file by pw.x is very different
from the expected. why ?

from ge.pw.out file i have ( created by pw.x for above input file)
Cartesian axes
    site n.     atom                  positions (alat units)
         1           Ti  tau(   1) = (   0.5000000   0.5000000   0.3219736
)
         2           Ti  tau(   2) = (   0.0000000   0.0000000   0.0000000
)
         3           O   tau(   3) = (   0.0000000   0.0000000   0.4475434
)
         4           O   tau(   4) = (   0.5000000   0.5000000   0.1255697
)
         5           O   tau(   5) = (   0.5000000   0.5000000   0.5183776
)
         6           O   tau(   6) = (   0.0000000   0.0000000   0.1964039
)

but the atomic positions are (in crystal unit )
 Ti    0.000000000         0.000000000         0.000000000
 Ti    0.500000000         0.500000000         0.500000000
  O    0.305299997         0.305299997         0.000000000
  O    0.694700003         0.694700003         0.000000000
  O    0.194700003         0.805299997         0.500000000
  O    0.805299997         0.194700003         0.500000000

my second question is

2) why QE is not giving correct atomic position if i use crystal_sg option ?

cay anyone help me in this regard. with this mail i have enclosed the
output file for the given input file
Thank you


*================================*

*Muthu V*

*Sri Paramakalyani College*

*Alwarkurichi================================*
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