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Problems: Difference between revisions
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→IDXREF produces too short cell parameter(s)
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PARAMETERS OF THE REDUCED CELL (ANGSTROEM & DEGREES) | PARAMETERS OF THE REDUCED CELL (ANGSTROEM & DEGREES) | ||
34.71 84.72 213.67 90.35 90.27 90.06 | 34.71 84.72 213.67 90.35 90.27 90.06 | ||
This clearly indicates that the third axis above the table (with 1/length=34.71) actually should be twice that size. If this happens, the histogram of indexed spots often has two equally-large subtrees: | Do you see the half-integer difference vectors in the last column? This clearly indicates that the third axis above the table (with 1/length=34.71) actually should be twice that size. If this happens, the histogram of indexed spots often has two equally-large subtrees: | ||
SUBTREE POPULATION | SUBTREE POPULATION | ||
| Line 154: | Line 154: | ||
5 6 | 5 6 | ||
Remedy: take the reduced cell below the table, but double the 34.71, and stick it into the line | Remedy: take the reduced cell (as found below the table), but double the 34.71, and stick it into the line | ||
UNIT_CELL_CONSTANTS=69.42 84.72 213.67 90.35 90.27 90.06 | UNIT_CELL_CONSTANTS=69.42 84.72 213.67 90.35 90.27 90.06 | ||
To make XDS use that line, specify | in XDS.INP. To make XDS actually ''use'' that line, specify | ||
SPACE_GROUP_NUMBER=1 | SPACE_GROUP_NUMBER=1 | ||
and leave the space group determination for later. | and leave the space group determination for later. | ||
| Line 162: | Line 162: | ||
Alternatively, try several well-separated SPOT_RANGEs instead of 1. For example, instead of | Alternatively, try several well-separated SPOT_RANGEs instead of 1. For example, instead of | ||
SPOT_RANGE=1 900 | SPOT_RANGE=1 900 | ||
try | try e.g. | ||
SPOT_RANGE=1 100 | SPOT_RANGE=1 100 | ||
SPOT_RANGE=801 900 | SPOT_RANGE=801 900 | ||
In | In the cases where I've tried this, this splitting of SPOT_RANGE into several wedges always resulted in IDXREF picking up the correct cell. | ||
The reason for the indexing failure in these cases seems to be the fact that the crystal changed its orientation within the SPOT_RANGE by more than ~ 0.1°. | |||
=== IDXREF prints !!! WARNING !!! message === | === IDXREF prints !!! WARNING !!! message === | ||