标题: Symmetry Operation [打印本页] 作者: OLS 时间: 2009-2-2 22:45 标题: Symmetry Operation Symmetry Operation $ G' |( t& W/ _# ] o( U! G& j
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. 7 ?5 s4 a9 P- n/ o V( J/ I/ ]
The Inversion Operation takes : r* }8 F% P C4 f8 q
(x,y,z)=>(-x,-y,-z) # I5 b: r+ \( h7 R/ O4 W7 F 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. % T$ r1 K! |/ @) t3 YThe Mirror Plane symmetry operation takes 5 ~) a5 X8 k `8 N! Q6 l(x,y,z)=>(x,y,-z)=>(x,-y,z)9 V- Y. Y! c6 C1 Y" o* c8 r
etc., which is equivalent to 2.