[Wien] Abvout the space groups P63mmc (194) and P3m1 (156)

[Gavin Abo]

sgroup gives me space group 194 for your structure. You just need to 
select the general lattice H and remove the special labels (that 
indicate to WIEN2k that atoms should be non-equivalent [ 
http://www.wien2k.at/reg_user/faq/supercells.html ]):

username at computername:~/wiendata/GaS-vdw$ ls
GaS-vdw.struct
username at computername:~/wiendata/GaS-vdw$ x sgroup
0.0u 0.0s 0:00.00 0.0% 0+0k 0+8io 0pf+0w
username at computername:~/wiendata/GaS-vdw$ grep "name of space group" 
*.outputsgroup
Number and name of space group: 156 (P 3 m 1) <= sgroup finds 156 
(because special labels were used to force equivalent atoms as 
non-equivalent atoms)

Struct file with space group 194 and special labels:

username at computername:~/wiendata/GaS-vdw$ sed -n "2p" GaS-vdw.struct
H   LATTICE,NONEQUIV.ATOMS:  8 194_P63/mmc
username at computername:~/wiendata/GaS-vdw$ sed -n "7p" GaS-vdw.struct
Ga1        NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "13p" GaS-vdw.struct
Ga2        NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "19p" GaS-vdw.struct
Ga3        NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "25p" GaS-vdw.struct
Ga4        NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "31p" GaS-vdw.struct
S 5        NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0
username at computername:~/wiendata/GaS-vdw$ sed -n "37p" GaS-vdw.struct
S 6        NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0
username at computername:~/wiendata/GaS-vdw$ sed -n "43p" GaS-vdw.struct
S 7        NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0
username at computername:~/wiendata/GaS-vdw$ sed -n "49p" GaS-vdw.struct
S 8        NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0

username at computername:~/wiendata/GaS-vdw$ gedit GaS-vdw.struct

Struct file with general H lattice (space group 194 removed) and no 
special labels:

username at computername:~/wiendata/GaS-vdw$ sed -n "2p" GaS-vdw.struct
H   LATTICE,NONEQUIV.ATOMS: 8
username at computername:~/wiendata/GaS-vdw$ sed -n "7p" GaS-vdw.struct
Ga         NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "13p" GaS-vdw.struct
Ga         NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "19p" GaS-vdw.struct
Ga         NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "25p" GaS-vdw.struct
Ga         NPT=  781  R0=0.00005000 RMT=    2.2600   Z: 31.0
username at computername:~/wiendata/GaS-vdw$ sed -n "31p" GaS-vdw.struct
S          NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0
username at computername:~/wiendata/GaS-vdw$ sed -n "37p" GaS-vdw.struct
S          NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0
username at computername:~/wiendata/GaS-vdw$ sed -n "43p" GaS-vdw.struct
S          NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0
username at computername:~/wiendata/GaS-vdw$ sed -n "49p" GaS-vdw.struct
S          NPT=  781  R0=0.00010000 RMT=    1.9700   Z: 16.0

username at computername:~/wiendata/GaS-vdw$ x nn
  specify nn-bondlength factor: (usually=2) [and optionally dlimit, 
dstmax (about
   1.d-5, 20)]
2
...
  WARNING: Mult not equal. PLEASE CHECK outputnn-file
  WARNING: ityp not equal. PLEASE CHECK outputnn-file

   NN created a new GaS-vdw.struct_nn file
NN created a new CASE.STRUCT_NN FILE
0.0u 0.0s 0:00.73 5.4% 0+0k 0+128io 0pf+0w
username at computername:~/wiendata/GaS-vdw$ cp GaS-vdw.struct_nn 
GaS-vdw.struct
username at computername:~/wiendata/GaS-vdw$ x sgroup
0.0u 0.0s 0:00.00 0.0% 0+0k 0+8io 0pf+0w
username at computername:~/wiendata/GaS-vdw$ cp GaS-vdw.struct_sgroup 
GaS-vdw.struct
username at computername:~/wiendata/GaS-vdw$ grep "name of space group" 
*.outputsgroup
Number and name of space group: 194 (P 63/m m c) <= sgroup finds 194

On 3/18/2016 11:28 AM, Osama Yassin wrote:
> ​Dear Prof Blaha
>
> I have a question related​ to the symmery of the lattice of GaS. It is 
> reoprted that GaS has a hexagonal crystal structure with space group 
> P63mmc (No. 194). Both the Ga and S atoms ocuupy the 4f site. However, 
> the sgroup of the Wien2k determines the structure to be in space group 
> P3m1 (156).
>
> I igonred the proposed structure but why it is not detecting the space 
> group P63mmc?.
>
> Tha structure file is attached.
>
> Best wishes
>
> O A Yassin
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