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Centric and acentric reflections: Difference between revisions
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(h,k,l) is centric if there is a symop g(x)=R_g*x+t_g in G such that R_g*(h,k,l)=(-h,-k,-l) | (h,k,l) is centric if there is a symop g(x)=R_g*x+t_g in G such that R_g*(h,k,l)=(-h,-k,-l) | ||
For example all reflection in the zone (h,k,0) are centrics in all space groups with twofold axes down c. | |||
Theorem: '''The phase of a centric reflection is restricted to phi(h,k,l)=pi*(h*tx_g+k*ty_g+l*tz_g) plus or minus any integer number of pi''' | Theorem: '''The phase of a centric reflection is restricted to phi(h,k,l)=pi*(h*tx_g+k*ty_g+l*tz_g) plus or minus any integer number of pi''' | ||