[Pw_forum] to extract k-point from bilbao crystallographic server

Abolore Musari abmus007 at gmail.com
Thu Jun 9 07:57:14 CEST 2011


Dear all QE users
I am so sorry to ask this question I have been to crystallographic server to
extract the coordinate for my  k-poiint card for space group Fd-3m. the page
is displayed below but I dont know how to extract my k-point from this page
i would be grateful if U can explain how I can get the coordinates for my k
point. Please I would be grateful for your assistance.


Abolore Musari
Dept Of Physics
University Of Agriculture, Nigeria.
The k-vector types of space group 227 [*F**d*-3*m*] (Table for arithmetic
crystal class m -3 mF)Fm-3m-Oh5 (225) to Fd-3c- Oh8(228)Reciprocal space
group (Im-3m)*, No.229
Brillouin zone<http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-kv-list?gnum=227&fig=fm3qmf>


k-vector descriptionWyckoff PositionITA description*CDML***Conventional-ITA*
*ITA**Coordinates**Label**Primitive*GM0,0,00,0,0a2m-3m 0,0,0 X1/2,0,1/20,1,0
b64/mm.m 0,1/2,0 L1/2,1/2,1/21/2,1/2,1/2c8.-3m 1/4,1/4,1/4 W1/2,1/4,3/4
1/2,1,0d12-4m.2 1/4,1/2,0 DTu,0,u0,2u,0e124m.m 0,y,0 : 0 < y < 1/2 LDu,u,u
u,u,uf16.3m x,x,x : 0 < x < 1/4 V1/2,u,1/2+u2u,1,0g24mm2.. x,1/2,0 : 0 < x <
1/4 SMu,u,2u ex2u,2u,0h24m.m2 x,x,0 : 0 < x <= 3/8 S1/2+u,2u,1/2+u ex2u,1,2u
h24m.m2 x,1/2,x : 0 < x < 1/8 S~SM1=[K M]h24m.m2 x,x,0 : 3/8 < x < 1/2 SM SM
1=[GM M]h24m.m2 x,x,0 : 0 < x < 1/2
Q1/2,1/4+u,3/4-u1/2,1-2u,2ui48..21/4,1/2-y,y : 0 < y < 1/4
Au,-u+v,v ex-2u+2v,2u,0j48m.. x,y,0 : 0 < x < y <= 3/8 U
U x,y,0 : 0 < x < 3/4-y < y < 1/2 B1/2+u,u+v,1/2+v ex2v,1,2uj48m.. x,1/2,z :
0 < z < x <= 1/4-z B~B1=[K M W]j48m.. x,y,0 : 3/4-y <= x < y < 1/2 A B1=[GM
M X]j48m.. x,y,0 : 0 < x < y < 1/2 Cu,u,v exv,v,-v+2uk48..m x,x,z : 0 < z <
x <= 3/8-z/2 Ju,v,u[GMXUL] exv,-v+2u,vk48..m x,y,x : 0 < x < y <= 1/2-x U
U x,y,x : 1/4 < y < 1/2, 1/2-y < x < 3/8-y/2 J~J1=[GM L X3] + [L K
M]k48..mx,x,z : 0 < x < z <= 1/2-x U
U x,x,z : 0 < z < 1/4, 3/8-z/2 < x < 1/2-z C + J1=[GM M X3] \ [GM
L]k48..mx,x,z : 0 < z < 1/2 -x < 1/2, x!= z
GPu,v,w-u+w+v,u+w-v,u-w+vl961 x,y,z : 0 < z < x < y < 1/2-x U
U x,y,z : 0 < z < 1/2-y < x < y < 1/2 U
U x,y,1/2-y : 1/4 < y < 1/2; 1/2-y < x < 1/4.



* Cracknell, A. P., Davies, B.L., Miller, S. C., and Love, W. F. (1979).
Kronecker Product Tables. Vol. 1. General Introduction and Tables of
Irreducible Representations of Space Groups. New York: IFI/Plenum.
The asymmetric unit of ITA is obtained from that used in these tables by
reflectionthrough the plane x,x,z .
The asymmetric unit is obtained from the representation domain of CDML by
the equivalence
[L K W M] ~[L U W X] through the two-fold rotation around the axis Q.
Wing: [GM L X3] x,x,z: 0 < x < z < 1/2-x

The transformation matrix that relates the primitive (CDML) base with the
conventional-ITA is -*a*+*b*+*c*,* **a*-*b*+*c*,* **a*+*b*-*c*


If you want to identify a *k*-vector you have to introduce: 1. The
reciprocal bases:  primitive (CDML)  conventional dual (ITA)     2.
The *k*-vector:
 kx   ky   kz
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