The actual vibrations don't exist at 100 K (similar to the case of B-factors/ADPs, sometimes called mildly misleadingly "temperature factors"), but are rather "frozen" where they were when they get cold. So a colder cryo stream would not help.
JPK -----Original Message----- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of D Bonsor Sent: Thursday, January 19, 2017 3:35 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Anisotropy and temperature A PhD student asked me what causes diffraction anisotropy. Quoting from the Diffraction Anisotropy Server webpage that it is caused by whole-body anisotropic vibration of unit cells. He asked whether a colder cyrostream could improve anisotropy. My answer would be yes, as colder temperatures would lower the vibrations. My two questions are; (1) am I right? and (2) if so, has it ever been done before in practice? Thanks, Dan
