Got the references, and I will check them out. Thanks a lot! Best Regards, Hailiang
> These papers might help: > > J. Appl. Cryst. (1997). 30, 396-399, F. M. D. Vellieux and B. W. Dijkstra > > J. Appl. Cryst. (1997). 30, 400-401, F. M. D. Vellieux > > Speaking of 3fo2fc or 5fo3fc, ... etc maps (see classic works on this > published 30+ years ago), I guess the main rationale for using them in > those cases arises from the facts that > > 2Fo-Fc = Fo + (Fo-Fc), > 3Fo-2Fc = Fo +2(Fo-Fc) > > and so on, and not from whether the one map is more (or less) model > biased than the other one. > > Randy Read (1986) showed that 2mFo-DFc is least model biased. The m and > D coefficients has to be computed using test reflections (Urzhumtsev et > al, 199?). To be precise, it is actually > > 2mFo-DFc for acentric reflections > and mFo for centric reflections > > Pavel. > > > On 7/29/10 12:12 PM, Hailiang Zhang wrote: >> Hi, >> >> I frequently find 3mFo-2DFc maps have been used for model building. I am >> not sure whether they have less model bias than 2mFo-DFc maps, and I >> appreciate for any references. >> >> Best Regards, Hailiang > > >
