标题: Symmetry Operation [打印本页] 作者: OLS 时间: 2009-2-2 22:45 标题: Symmetry Operation Symmetry Operation # _- `- y: f9 X2 T8 ]Symmetry operations include the Improper Rotation, Inversion Operation, Mirror Plane, and Rotation. Together, these operations create 32 crystal classes corresponding to the 32 Point Groups. - _* A- u9 ]- }6 E1 `" \
The Inversion Operation takes 0 H# y! [ d) q* X- c1 ]
(x,y,z)=>(-x,-y,-z) 4 G9 V& S/ `" I, S9 m3 V( p and is denoted i. When used in conjunction with a Rotation, it becomes an Improper Rotation. An Improper Rotation by 360/n . For periodic crystals, the Crystallography Restriction allows only the Improper Rotations 1, 2, 3, 4, and 6. % p B8 J2 v& D. y% B$ T$ i& }+ T9 NThe Mirror Plane symmetry operation takes 6 a1 R- r' N4 v5 c5 R
(x,y,z)=>(x,y,-z)=>(x,-y,z)3 R, X/ L- ~5 z" O8 q1 G
etc., which is equivalent to 2.