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Item _phasing_MIR_der.R_cullis_anomalous
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Description
Residual factor R~cullis,ano~ for anomalous reflections in this
derivative.
The Cullis R factor was originally defined only for centric
reflections. It is, however, also a useful statistical
measure for anomalous reflections, which is how it is used in
this data item.
This is tabulated for acentric terms. Any value <1.0 means
there is some contribution to the phasing from the anomalous
data.
sum| |Fph+~obs~Fph-~obs~ - Fh+~calc~ - Fh-~calc~| |
R~cullis,ano~ = ---------------------------------------------------
sum|Fph+~obs~ - Fph-~obs~|
Fph+~obs~ = the observed positive Friedel structure factor
amplitude for the derivative
Fph-~obs~ = the observed negative Friedel structure factor
amplitude for the derivative
Fh+~calc~ = the calculated positive Friedel structure factor
amplitude from the heavy atom model
Fh-~calc~ = the calculated negative Friedel structure factor
amplitude from the heavy atom model
sum is taken over the specified reflections
Ref: Cullis, A. F., Muirhead, H., Perutz, M. F., Rossmann, M. G.
& North, A. C. T. (1961). Proc. Roy. Soc. A265, 15-38.
Category
phasing_mir_der
Mandatory Code
no
Data Type Code
float
Enumeration Range
Minimum Value |
Maximum Value |
0.0 |
n.a. |
0.0 |
0.0 |
Alias Names
Alias Name |
Dictionary |
Version |
_phasing_MIR_der.ebi_Rcullis_anomalous |
ebi_extensions |
1.0 |
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