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SHELX C/D/E: Difference between revisions
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In difficult cases SHELXD can be run with different SHEL instructions, e.g. truncating the data in steps of 0.1 Å, and the CC values compared. This is especially convenient if a computer farm can be used to run the jobs in parallel. If the best CC is plotted against the resolution, a local maximum (when also observed for the CC(weak) values) may indicate a correct solution.<br> | In difficult cases SHELXD can be run with different SHEL instructions, e.g. truncating the data in steps of 0.1 Å, and the CC values compared. This is especially convenient if a computer farm can be used to run the jobs in parallel. If the best CC is plotted against the resolution, a local maximum (when also observed for the CC(weak) values) may indicate a correct solution.<br> | ||
The default weights for the CC are 1/ | The default weights for the CC are 1/σ(E)<sup>2</sup>. The presence of one or two reflections with very low esds can lead to unreasonably high values of the CC for wrong solutions. If the esds are unreliable it is advisable to use 'CCWT 0.1' in the .ins file for SHELXD. The precision of the heavy atom coordinates can be improved, at the cost of the CPU time, by making the Fourier grid finer (e.g. FRES 4 instead of the default 2.5).<br> | ||
== SHELXE == | == SHELXE == | ||