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Space group determination: Difference between revisions
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The user may experiment with adjusting these values to make the automatic mode of space group determination more successful. However, it is much easier to just input the space group and cell parameters that the user thinks are correct. | The user may experiment with adjusting these values to make the automatic mode of space group determination more successful. However, it is much easier to just input the space group and cell parameters that the user thinks are correct. | ||
== Screw axes == | |||
The current version makes no attempt to find out about screw axes. It is assumed that the user checks the table in CORRECT.LP entitled "REFLECTIONS OF TYPE H,0,0 0,K,0 0,0,L OR EXPECTED TO BE ABSENT (*)", and identifies whether the intensities follow the rules | |||
#* along each axis in reciprocal space, a two-fold screw axis (theoretically) results in zero intensity for the odd-numbered (e.g., K = 2*n + 1) reflections. | |||
#* similarly, a three-fold screw axis (theoretically) results in zero intensity for the reflections of type 3*n+1 and 3*n+2, leaving the 3*n reflections as candidates for medium to strong reflections. | |||
#* analogously for four-fold and six-fold axes. | |||
== Notes == | == Notes == | ||