标题: Symmetry Operation [打印本页] 作者: OLS 时间: 2009-2-2 22:45 标题: Symmetry Operation Symmetry Operation / n+ b$ z# j. ]" d( v) d' {: X* vSymmetry operations include the Improper Rotation, Inversion Operation, Mirror Plane, and Rotation. Together, these operations create 32 crystal classes corresponding to the 32 Point Groups. 3 ^9 a6 ]( M/ H2 JThe Inversion Operation takes ! _; c. F+ ^% k5 n1 t8 F2 m(x,y,z)=>(-x,-y,-z)5 _2 G8 c% r* E0 @" t
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. / ~9 |6 ?- N/ o% f$ m: E, Z1 dThe Mirror Plane symmetry operation takes * z& [- k" `2 V( U
(x,y,z)=>(x,y,-z)=>(x,-y,z); y4 U: h" Z/ r2 D6 ?
etc., which is equivalent to 2.