Hi Robbie, On Wed, Jul 15, 2020 at 07:23:15PM +0000, Robbie Joosten wrote: > At the same time if you have a a more relaxed approach to restraints > than you might find systematic deviations in bond lengths. A test > for that has been in WHAT_CHECK for decades and it actually works > surprisingly well to detect cell dimension problems.
Indeed. > That said, the problem is uncommon now. Not so sure about that: we all rely on an accurate value of the energy/wavelength from the instrument/beamline - and if that is off (for whatever reasons) it will result in incorrect cell dimensions and a systematic deviation from the various restraints. This would even affect the best experiment done on the best crystal ... so fairly easy to spot at the refinement stage, especially if such an energy/wavelength offset is constant over a long period of time on a given instrument. To spot this at the data collection stage one would hope that at some point a crystal with very pronounced ice-rings will be looked at properly (and the fact these are not where we expect them to should cause some head-scratching). Cheers Clemens ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
