[Pw_forum] Zr supercell with ibrav=4

[Krishnendu Mukherjee]

Dear experts,

 I am interested in calculation of elastic constants of Zr using a
supercell of 2*2*2. I created this supercell in VESTA, using Space group
No. 194, P 63/m m c. For the unit cell structure Parameters I used:

0.333333 0.666667 0.25
and
0.666667 0.333333 0.75

I have input the atomic positions into the following input:

&control
    calculation = 'scf'
    restart_mode='from_scratch',
    prefix='zr',
    tstress = .true.,
   tprnfor = .true.,
    pseudo_dir = '/home/krishna/QE/qe-6.2/pseudo/',
    outdir='/home/krishna/QE/qe-6.2/tempdir/'
 /
 &system
    ibrav=  4,
    celldm(1) =12.241645,
    celldm(3) = 1.59185,
    nat= 16,
    ntyp= 1,
    ecutwfc=50.0,
   ecutrho = 430,
   occupations='smearing',
   smearing='marzari-vanderbilt',
   degauss=0.02
   starting_magnetization(1) = 0.7,
 /
 &electrons
    conv_thr =  1.0d-12
 /
ATOMIC_SPECIES
 Zr  91.22  Zr.pz-spn-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS (angstrom)
Zr    0.000000    1.870038    1.289000
Zr    3.239000    3.740075    9.023001
Zr    1.619500    4.675094    1.289000
Zr    1.619500    0.935019    9.023001
Zr   -1.619500    4.675094    1.289000
Zr    4.858500    0.935019    9.023001
Zr    3.239000    3.740075    3.867000
Zr    1.619500    0.935019    3.867000
Zr    4.858500    0.935019    3.867000
Zr    0.000000    1.870038    6.445000
Zr    1.619500    4.675094    6.445000
Zr   -1.619500    4.675094    6.445000
Zr    3.239000    1.870038    1.289000
Zr    0.000000    3.740075    9.023001
Zr    0.000000    3.740075    3.867000
Zr    3.239000    1.870038    6.445000
K_POINTS AUTOMATIC
5 5 3 0 0 0

However, in out.1_0, in notice that

Space group nymber  164

Is it an error, because I generated the supercell using space group number
194?

 If it is an error can you please let me know, how to modify the input?

However, when I ran the program with an unit cell of two atoms the space
group number was rightly identified as 194.

Thanks,
Best regards,
Krish

-- 
Dr. Krishnendu Mukherjee,

Principal Scientist,
CSIR-NML,
Jamshedpur.
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