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Dear Xiangang Wan,
<br>
there is a section in the manual and a few thousand posts in the
mailing list archive<br>
explaining this issue. <br>
best,<br>
<br>
Stefano de Gironcoli - SISSA and DEMOCRITOS<br>
<br>
<br>
thereOn 08/17/2011 08:23 AM, Lo_wan_2005XW wrote:
<blockquote cite="mid:COL103-W1259C65C97F8EF50E59E80B3280@phx.gbl"
type="cite">
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Dear all,
I am studying a compound with P63/m structure.
But the program complain:
warning: symmetry operation # 2 not allowed. fractional translation:
0.0000000 0.0000000 0.5000000 in crystal coordinates
warning: symmetry operation # 5 not allowed. fractional translation:
0.0000000 0.0000000 0.5000000 in crystal coordinates
warning: symmetry operation # 6 not allowed. fractional translation:
0.0000000 0.0000000 0.5000000 in crystal coordinates
warning: symmetry operation # 14 not allowed. fractional translation:
0.0000000 0.0000000 0.5000000 in crystal coordinates
warning: symmetry operation # 17 not allowed. fractional translation:
0.0000000 0.0000000 0.5000000 in crystal coordinates
warning: symmetry operation # 18 not allowed. fractional translation:
0.0000000 0.0000000 0.5000000 in crystal coordinates
Our compound has P63/m structure (176 space group). And following is the setup:
--------------------------------------------
&system
ibrav= 4, celldm(1) =10.726090,
celldm(3)=1.25440, nat= 12, ntyp= 2, ecutwfc =35.0,ecutrho=300
occupations='smearing', smearing='marzari-vanderbilt', degauss=0.05
/
&electrons
diagonalization='david'
mixing_beta = 0.7
/
ATOMIC_SPECIES
La 138.9055 La.pbe-n-bpaw.UPF
Si 28.0855 Si.pbe-n-van.UPF
ATOMIC_POSITIONS crystal
La 0.00000000 0.00000000 0.50000000
La 0.00000000 0.00000000 0.00000000
Si 0.48000000 0.99000000 0.75000000
Si 0.01000000 0.49000000 0.75000000
Si 0.51000000 0.52000000 0.75000000
Si 0.52000000 0.01000000 0.25000000
Si 0.99000000 0.51000000 0.25000000
Si 0.49000000 0.48000000 0.25000000
Si 0.333333333 0.666666666 0.50000000
Si 0.666666666 0.333333333 0.00000000
Si 0.666666666 0.333333333 0.50000000
Si 0.333333333 0.666666666 0.00000000
K_POINTS automatic
6 6 5 0 0 0
--------------------------------------------
Following is "atomic positions are in cartesian coordinates" printed by the program
site n. atom positions (alat units)
1 La tau( 1) = ( 0.0000000 0.0000000 0.6272000 )
2 La tau( 2) = ( 0.0000000 0.0000000 0.0000000 )
3 Si tau( 3) = ( -0.0150000 0.8573651 0.9408000 )
4 Si tau( 4) = ( -0.2350000 0.4243524 0.9408000 )
5 Si tau( 5) = ( 0.2500000 0.4503332 0.9408000 )
6 Si tau( 6) = ( 0.5150000 0.0086603 0.3136000 )
7 Si tau( 7) = ( 0.7350000 0.4416730 0.3136000 )
8 Si tau( 8) = ( 0.2500000 0.4156922 0.3136000 )
9 Si tau( 9) = ( 0.0000000 0.5773503 0.6272000 )
10 Si tau( 10) = ( 0.5000000 0.2886751 0.0000000 )
11 Si tau( 11) = ( 0.5000000 0.2886751 0.6272000 )
12 Si tau( 12) = ( 0.0000000 0.5773503 0.0000000 )
I cannot find any error in the setup. So why there is a warning about the symmetry operation? Does it serious problem?
Thanks
Xiangang Wan
Department of Physics
Nanjing University
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