[Pw_forum] Problem regarding identification of space group of Zr15Nb1 cell
Krishnendu Mukherjee
krishnendu.mukherjee789 at gmail.com
Fri Feb 9 10:48:12 CET 2018
Dear Experts,
I have created a Zr15Nb1 cell containing 15 Zr atoms and 1 Nb atom using
the space group P 63/m m c, (space group number 194).
But, when I try to calculate the elastic constant of it using the
thermo_pw, I find, pwscf recognizes wrong space group (No. 187). Please
find below my input:
cat > thermo_control << EOF
&INPUT_THERMO
what='mur_lc_elastic_constants',
frozen_ions=.FALSE.
/
EOF
cat > zr.elastic.in << EOF
&control
calculation = 'scf'
restart_mode='from_scratch',
prefix='zr',
verbosity='high',
tstress = .true.,
tprnfor = .true.,
pseudo_dir = '$PSEUDO_DIR/',
outdir='$TMP_DIR/'
/
&system
ibrav= 4,
celldm(1) =12.241644950000000E00,
celldm(3) = 1.591850000000000E00,
nat= 16,
ntyp= 2,
ecutwfc=50.0,
ecutrho = 180,
nr1=90,
nr2=90,
nr3=144,
occupations='smearing',
smearing='marzari-vanderbilt',
degauss=0.02
starting_magnetization(1) = 0.7,
use_all_frac = .true.
/
&electrons
conv_thr = 1.0d-9
/
ATOMIC_SPECIES
Zr 91.22 Zr.pz-spn-kjpaw_psl.1.0.0.UPF
Nb 92.906 Nb.pz-spn-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS (crystal)
Zr 0.166666666666667E+00 0.333333333333333E+00
0.125000000000000E+00
Zr 0.833333333333333E+00 0.666666666666667E+00
0.875000000000000E+00
Zr 0.666666666666667E+00 0.833333333333333E+00
0.125000000000000E+00
Zr 0.333333333333333E+00 0.166666666666667E+00
0.875000000000000E+00
Zr 0.166666666666667E+00 0.833333333333333E+00
0.125000000000000E+00
Zr 0.833333333333333E+00 0.166666666666667E+00
0.875000000000000E+00
Zr 0.833333333333333E+00 0.666666666666667E+00
0.375000000000000E+00
Zr 0.333333333333333E+00 0.166666666666667E+00
0.375000000000000E+00
Zr 0.833333333333333E+00 0.166666666666667E+00
0.375000000000000E+00
Nb 0.166666666666667E+00 0.333333333333333E+00
0.625000000000000E+00
Zr 0.666666666666667E+00 0.833333333333333E+00
0.625000000000000E+00
Zr 0.166666666666667E+00 0.833333333333333E+00
0.625000000000000E+00
Zr 0.666666666666667E+00 0.333333333333333E+00
0.125000000000000E+00
Zr 0.333333333333333E+00 0.666666666666667E+00
0.875000000000000E+00
Zr 0.333333333333333E+00 0.666666666666667E+00
0.375000000000000E+00
Zr 0.666666666666667E+00 0.333333333333333E+00
0.625000000000000E+00
K_POINTS AUTOMATIC
5 5 3 0 0 0
*********************************************************************************************************
Below I have included some part of the output:
Starting atomic positions in crystallographic axes:
site n. atom positions (cryst. coord.)
1 Zr tau( 1) = ( 0.1666667 0.3333333 0.1250000 )
2 Zr tau( 2) = ( 0.8333333 0.6666667 0.8750000 )
3 Zr tau( 3) = ( 0.6666667 0.8333333 0.1250000 )
4 Zr tau( 4) = ( 0.3333333 0.1666667 0.8750000 )
5 Zr tau( 5) = ( 0.1666667 0.8333333 0.1250000 )
6 Zr tau( 6) = ( 0.8333333 0.1666667 0.8750000 )
7 Zr tau( 7) = ( 0.8333333 0.6666667 0.3750000 )
8 Zr tau( 8) = ( 0.3333333 0.1666667 0.3750000 )
9 Zr tau( 9) = ( 0.8333333 0.1666667 0.3750000 )
10 Nb tau( 10) = ( 0.1666667 0.3333333 0.6250000 )
11 Zr tau( 11) = ( 0.6666667 0.8333333 0.6250000 )
12 Zr tau( 12) = ( 0.1666667 0.8333333 0.6250000 )
13 Zr tau( 13) = ( 0.6666667 0.3333333 0.1250000 )
14 Zr tau( 14) = ( 0.3333333 0.6666667 0.8750000 )
15 Zr tau( 15) = ( 0.3333333 0.6666667 0.3750000 )
16 Zr tau( 16) = ( 0.6666667 0.3333333 0.6250000 )
The energy minimization will require 9 scf calculations
The point group 107 D_3h (-62m) is compatible with the Bravais lattice.
The rotation matrices with the order used inside thermo_pw are:
12 Sym. Ops. (no inversion) found (10 have fractional translation)
s frac. trans.
isym = 1 identity
cryst. s( 1) = ( 1 0 0 )
( 0 1 0 )
( 0 0 1 )
cart. s( 1) = ( 1.000 0.000 0.000 )
( 0.000 1.000 0.000 )
( 0.000 0.000 1.000 )
isym = 2 180 deg rotation - cart. axis [0,1,0]
cryst. s( 2) = ( -1 0 0 )
( 1 1 0 )
( 0 0 -1 )
cart. s( 2) = ( -1.000 0.000 0.000 )
( 0.000 1.000 0.000 )
( 0.000 0.000 -1.000 )
isym = 3 120 deg rotation - cryst. axis [0,0,1]
cryst. s( 3) = ( 0 1 0 )
( -1 -1 0 )
( 0 0 1 )
cart. s( 3) = ( -0.500 -0.866 0.000 )
( 0.866 -0.500 0.000 )
( 0.000 0.000 1.000 )
isym = 4 120 deg rotation - cryst. axis [0,0,-1]
cryst. s( 4) = ( -1 -1 0 )
( 1 0 0 )
( 0 0 1 )
cart. s( 4) = ( -0.500 0.866 0.000 )
( -0.866 -0.500 0.000 )
( 0.000 0.000 1.000 )
isym = 5 180 deg rotation - cryst. axis [1,-1,0]
cryst. s( 5) = ( 0 -1 0 )
( -1 0 0 )
( 0 0 -1 )
cart. s( 5) = ( 0.500 -0.866 0.000 )
( -0.866 -0.500 0.000 )
( 0.000 0.000 -1.000 )
isym = 6 180 deg rotation - cryst. axis [2,1,0]
cryst. s( 6) = ( 1 1 0 )
( 0 -1 0 )
( 0 0 -1 )
cart. s( 6) = ( 0.500 0.866 0.000 )
( 0.866 -0.500 0.000 )
( 0.000 0.000 -1.000 )
isym = 7 inv. 180 deg rotation - cart. axis [0,0,1]
cryst. s( 7) = ( 1 0 0 )
( 0 1 0 )
( 0 0 -1 )
cart. s( 7) = ( 1.000 0.000 0.000 )
( 0.000 1.000 0.000 )
( 0.000 0.000 -1.000 )
isym = 8 inv. 180 deg rotation - cart. axis [1,0,0]
cryst. s( 8) = ( -1 0 0 )
( 1 1 0 )
( 0 0 1 )
cart. s( 8) = ( -1.000 0.000 0.000 )
( 0.000 1.000 0.000 )
( 0.000 0.000 1.000 )
isym = 9 inv. 60 deg rotation - cryst. axis [0,0,1]
cryst. s( 9) = ( -1 -1 0 )
( 1 0 0 )
( 0 0 -1 )
cart. s( 9) = ( -0.500 0.866 0.000 )
( -0.866 -0.500 0.000 )
( 0.000 0.000 -1.000 )
isym = 10 inv. 60 deg rotation - cryst. axis [0,0,-1]
cryst. s(10) = ( 0 1 0 )
( -1 -1 0 )
( 0 0 -1 )
cart. s(10) = ( -0.500 -0.866 0.000 )
( 0.866 -0.500 0.000 )
( 0.000 0.000 -1.000 )
isym = 11 inv. 180 deg rotation - cryst. axis [0,1,0]
cryst. s(11) = ( 1 1 0 )
( 0 -1 0 )
( 0 0 1 )
cart. s(11) = ( 0.500 0.866 0.000 )
( 0.866 -0.500 0.000 )
( 0.000 0.000 1.000 )
isym = 12 inv. 180 deg rotation - cryst. axis [1,1,0]
cryst. s(12) = ( 0 -1 0 )
( -1 0 0 )
( 0 0 1 )
cart. s(12) = ( 0.500 -0.866 0.000 )
( -0.866 -0.500 0.000 )
( 0.000 0.000 1.000 )
point group D_3h (-62m)
there are 6 classes
the character table:
E 2C3 3C2 s_h 2S3 3s_v
A'_1 1.00 1.00 1.00 1.00 1.00 1.00
A'_2 1.00 1.00 -1.00 1.00 1.00 -1.00
E' 2.00 -1.00 0.00 2.00 -1.00 0.00
A''1 1.00 1.00 1.00 -1.00 -1.00 -1.00
A''2 1.00 1.00 -1.00 -1.00 -1.00 1.00
E'' 2.00 -1.00 0.00 -2.00 1.00 0.00
the symmetry operations in each class and the name of the first
element:
E 1
identity
2C3 3 4
120 deg rotation - cryst. axis [0,0,1]
3C2 2 6 5
180 deg rotation - cart. axis [0,1,0]
s_h 7
inv. 180 deg rotation - cart. axis [0,0,1]
2S3 9 10
inv. 60 deg rotation - cryst. axis [0,0,1]
3s_v 8 11 12
inv. 180 deg rotation - cart. axis [1,0,0]
Space group identification, 12 symmetries:
Bravais lattice 4 hexagonal
Point group number 21 / 107 D_3h (-62m)
Nonsymmorphic operations not found: All fractional translations vanish
Symmetries of the point group in standard order
1 E 1
2 i6z 57
3 3z 27
4 i2z 34
5 3-z 28
6 i6-z 58
7 i2x 36
8 2210 30
9 i2110 64
10 2y 3
11 i2010 63
12 21-10 29
Space group nymber 187
Space group P-6m2 (group number 187).
The origin coincides with the ITA tables.
The Laue class is D_6h(6/mmm)
In this class the elastic tensor is
( c11 c12 c13 . . . )
( c12 c11 c13 . . . )
( c13 c13 c33 . . . )
( . . . c44 . . )
( . . . . c44 . )
( . . . . . X )
X=(c11-c12)/2
It requires three strains: e1, e3, and e4
for a total of 12 scf calculations
*****************************************************************************************************
It will be great if you can help me in solving this problem,
Thanks,
Best regards,
Krishnendu
--
Dr. Krishnendu Mukherjee,
Principal Scientist,
CSIR-NML,
Jamshedpur.
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