[ccp4bb] m-3m vs. m-3

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: Re: Semet in non-auxotrophic strains (summary)
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2008-11-03

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From: " Thai Leong Yap
Date: 2008-11-03

Subject: m-3m vs. m-3
From: yanming Zhang shanmao62 {- at -} YAHOO {- dot -} COM
Date: 2008-11-03

Dear 'old' crystallographers,

During one case of structure solution, the data processing programs output incorrect space group-primitive cubic P4132, which later found out that the correct one should be face centerd cubic f23. This problem was caused by perfect twinning.

Now I'd like to invite you to help me understand, and explain in details,
WHY, IN CASE OF PERFECT TWINNING, THE LAUE GROUP m-3 WILL BE MIS-INDEXED TO m-3m by some data processing programs? I, sort of, understand the reason behind this is caused by the perfect twin operator which will emulate an additional 2-fold axis. But not fully understand the symmetry in details in this case. Your help and teaching are highly appreciated.

Yanming Zhang

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Semet in non-auxotrophic strains (summary)
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2008-11-03

Next message:
Subject: unsubscribe ccp4bb
From: " Thai Leong Yap
Date: 2008-11-03