Obviously it depends on degree of isomorphism - the Riso plot from SCALEPACK gives you a measure..
It would be hard to sort out phase change due to non-isomorphism v phase change from error - in measurements, substructure, etc But a practical guide - when doing phase extension from a SAD set of phases to a somewhat non-isomorphic native data set - using DM or something similar - the rule of thumb was that it pays to start at a low resolution where the isomophism is still reasonable and extend in small steps. Eleanor On 27 January 2015 at 08:28, Frank von Delft <frank.vonde...@sgc.ox.ac.uk> wrote: > Hi all - anybody know the answer, or can tell me where to look: > > Regarding that oft-stated rule-of-thumb from the 60s (Blow? Crick?), that > a 1% change in cell parameters causes a 3% change in intensities: is there > an equivalent statement to be made about how phases change with increasing > non-isomorphism - and related to that, at what point do maps become > unrecognisable? > > Or another way to ask this: how isomorphous must two datasets be for a > phase transplant from one to the other to be valid? > > Cheers > Frank >
