[phenixbb] Refining f'/f"?
Nathaniel Echols
NEchols at lbl.gov
Thu May 7 12:52:11 PDT 2009
On May 7, 2009, at 3:39 PM, Leigh Allen wrote:
> I collected at 1.0809A, which was the optimal wavelength for the
> beam at NSLS-X29. I will model them as MSEs. I guess the better
> question to ask is if I should be concerned with not having these
> negative peaks. Will it negatively affect my R-work/R-free if I
> continue to work with the data that's not been scaled to keep F+/F-
> separate?
At that wavelength f' is approximately -2 and f'' is 0.6, which are
much less than at the Se K edge:
http://skuld.bmsc.washington.edu/scatter/data/Se.dat
I would expect R/Rfree to improve slightly if you refine against F+/
F-, but if you do this and still see negative peaks, I wouldn't worry
about them. (Note: you still need to scale your data, just don't
average F+/F- - in HKL2000 clicking the "Anomalous" box in the scaling
window is sufficient.)
--------------------
Nathaniel Echols
Lawrence Berkeley Lab
510-486-5136
NEchols at lbl.gov
More information about the phenixbb
mailing list