On Wednesday, 13 May, 2015 17:51:59 Chen Zhao wrote: > Hi all, > > I am sorry about this question which I should have figured out earlier. For > point group determination, does the Rmeas consider Fridel pairs > differently?
A Friedel pair consists of the [hkl] and [-h-k-l] reflections. This pairing is independent of space group. So the agreement or lack of agreement between Friedel pairs is not informative about selection of point group or space group. You may be thinking of a Bijvoet pair, which consists of [hkl] and the Friedel mate of some symmetry equivalent of [hkl] within a particular spacegroup. But even in the presence of anomalous scattering I think that Bijvoet pairs are expected to agree with each other better than with a reflection not related by point group symmetry. > (although I think it should be...) This is because I saw a > derivative dataset collected at peak (from a demo) whose Rmeas is quite > high (>50 %) for all the space groups tested (including P1). However, the > native dataset has only <10 % Rmeas. Should I worry about the derivative > dataset? There seems to be multiple lattices in both datasets based on > IDXREF. > > You inputs are really appreciated! > > Sincerely, > Chen -- Ethan A Merritt Biomolecular Structure Center, K-428 Health Sciences Bldg MS 357742, University of Washington, Seattle 98195-7742
