Am 09.01.2008 um 20:48 schrieb Anastassis Perrakis:
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I actually think that inaccurate cells are a big source of misery in many refinements. I have found the idea of WhatCheck to actually check your cell by looking at the projection of bond lengths of certain types along the cell axes most useful. I would hardly advocate to measure your cell that way, but going back to you data and looking at the cell again would be worth it.
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There was a discussion many years ago on this bulletin board about unit cell scaling errors reported by WHAT_CHECK that resulted merely from some different dictionary values used in the refinement program (CNS, if I remember correctly) and in WHAT_CHECK, although both claimed to use the Engh & Huber parameters. This difference projected onto the unit cell axes resulted in a reported unit cell scaling error, that could not be fixed by iterative rescaling of the unit cell and refinement, and thus was an artifact. So, I wouldn't even trust the unit cells reported by WHAT_CHECK . . .

Best regards,

Dirk.

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Dirk Kostrewa
Gene Center, A 5.07
Ludwig-Maximilians-University
Feodor-Lynen-Str. 25
81377 Munich
Germany
Phone:  +49-89-2180-76845
Fax:    +49-89-2180-76999
E-mail: [EMAIL PROTECTED]
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