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INTERNATIONAL TABLES for CRYSTALLOGRAPHY |
Volume G |
Definition and Exchange of Crystallographic Data |
Definition:
Residual factor R for reflections that satisfy the resolution
limits established by _refine.ls_d_res_high and
_refine.ls_d_res_low and the observation limit established by
_reflns.observed_criterion.
_refine.ls_R_factor_obs should not be confused with
_refine.ls_R_factor_R_work; the former reports the results of a
refinement in which all observed reflections were used, the
latter a refinement in which a subset of the observed
reflections were excluded from refinement for the calculation
of a 'free' R factor. However, it would be meaningful to quote
both values if a 'free' R factor were calculated for most of
the refinement, but all of the observed reflections were used
in the final rounds of refinement; such a protocol should be
explained in _refine.details.
sum|F~obs~ - F~calc~|
R = ---------------------
sum|F~obs~|
F~obs~ = the observed structure-factor amplitudes
F~calc~ = the calculated structure-factor amplitudes
sum is taken over the specified reflections
Type: float
Mandatory item: no
Alias:Related item: _refine.ls_wR_factor_obs (alternate)
Category: refine
Copyright © 2005 International Union of Crystallography