A description of the method by which a subset of reflections was selected for exclusion from refinement so as to be used in the calculation of a 'free' R factor.
Examples: The data set was sorted with l varying most rapidly and h varying least rapidly. Every 10th reflection in this sorted list was excluded from refinement and included in the calculation of a 'free' R factor.
Residual factor Rmerge for all reflections that satisfy the resolution limits established by _reflns.d_resolution_high and _reflns.d_resolution_low.
sum~i~(sum~j~|F~j~ - <F>|)
Rmerge(F) = --------------------------
sumi(sumj
Fj = the amplitude of the jth observation of reflection i
sumi is taken over all reflections
sumj is taken over all observations of each reflection
Residual factor Rmerge for reflections that satisfy the resolution limits established by _reflns.d_resolution_high and _reflns.d_resolution_low and the observation limit established by _reflns.observed_criterion.
sum~i~(sum~j~|F~j~ - <F>|)
Rmerge(F) = --------------------------
sumi(sumj
Fj = the amplitude of the jth observation of reflection i
sumi is taken over all reflections
sumj is taken over all observations of each reflection
The smallest value in angstroms for the interplanar spacings for the reflection data. This is called the highest resolution.
The largest value in angstroms for the interplanar spacings for the reflection data. This is called the lowest resolution.
A description of special aspects of the data-reduction procedures.
Examples: Merging and scaling based on only those reflections with I > sig(I).
The method used for data reduction.
Note that this is not the computer program used, which is described in the SOFTWARE category, but the method itself.
This data item should be used to describe significant methodological options used within the data-reduction programs.
Examples: Profile fitting by method of Kabsch (1987). Scaling used spherical harmonic coefficients.
A description of reflection data not covered by other data names. This should include details of the Friedel pairs.
Maximum value of the Miller index h for the reflection data. This need not have the same value as _diffrn_reflns.limit_h_max.
Minimum value of the Miller index h for the reflection data. This need not have the same value as _diffrn_reflns.limit_h_min.
Maximum value of the Miller index k for the reflection data. This need not have the same value as _diffrn_reflns.limit_k_max.
Minimum value of the Miller index k for the reflection data. This need not have the same value as _diffrn_reflns.limit_k_min.
Maximum value of the Miller index l for the reflection data. This need not have the same value as _diffrn_reflns.limit_l_max.
Minimum value of the Miller index l for the reflection data. This need not have the same value as _diffrn_reflns.limit_l_min.
The total number of reflections in the REFLN list (not the DIFFRN_REFLN list). This number may contain Friedel-equivalent reflections according to the nature of the structure and the procedures used. The item _reflns.details describes the reflection data.
The number of reflections in the REFLN list (not the DIFFRN_REFLN list) classified as observed (see _reflns.observed_criterion). This number may contain Friedel-equivalent reflections according to the nature of the structure and the procedures used.
The criterion used to classify a reflection as 'observed'. This criterion is usually expressed in terms of a sigma(I) or sigma(F) threshold.
Examples:
2sigma(I)
The criterion used to classify a reflection as 'observed' expressed as an upper limit for the value of F.
The criterion used to classify a reflection as 'observed' expressed as a lower limit for the value of F.
The criterion used to classify a reflection as 'observed' expressed as an upper limit for the value of I.
The criterion used to classify a reflection as 'observed' expressed as a lower limit for the value of I.
The criterion used to classify a reflection as 'observed' expressed as a multiple of the value of sigma(F).
The criterion used to classify a reflection as 'observed' expressed as a multiple of the value of sigma(I).
The Pearson's correlation coefficient expressed as a decimal value between the average intensities from randomly selected half-datasets.
Ref: Karplus & Diederichs (2012), Science 336, 1030-33
R split measures the agreement between the sets of intensities created by merging odd- and even-numbered images from the overall data.
Ref: T. A. White, R. A. Kirian, A. V. Martin, A. Aquila, K. Nass, A. Barty
and H. N. Chapman (2012), J. Appl. Cryst. 45, 335-341
The R value for merging intensities satisfying the observed criteria in this data set.
The precision-indicating merging R factor value Rpim, for merging all intensities in this data set.
sum~i~ [1/(N~i~ - 1)]1/2^ sum~j~ | I~j~ - <I~i~> |
Rpim = --------------------------------------------------
sumi ( sumj Ij )
Ij = the intensity of the jth observation of reflection i
<Ii> = the mean of the intensities of all observations
of reflection i
Ni = the redundancy (the number of times reflection i
has been measured).
sumi is taken over all reflections
sumj is taken over all observations of each reflection.
Ref: Diederichs, K. & Karplus, P. A. (1997). Nature Struct. Biol. 4, 269-275. Weiss, M. S. & Hilgenfeld, R. (1997). J. Appl. Cryst. 30, 203-205. Weiss, M. S. (2001). J. Appl. Cryst. 34, 130-135.
The redundancy-independent merging R factor value Rrim, also denoted Rmeas, for merging all intensities in this data set.
sum~i~ [N~i~/(N~i~ - 1)]1/2^ sum~j~ | I~j~ - <I~i~> |
Rrim = ----------------------------------------------------
sum~i~ ( sum~j~ I~j~ )
I~j~ = the intensity of the jth observation of reflection i
<I~i~> = the mean of the intensities of all observations of
reflection i
N~i~ = the redundancy (the number of times reflection i
has been measured).
sum~i~ is taken over all reflections
sum~j~ is taken over all observations of each reflection.
Ref: Diederichs, K. & Karplus, P. A. (1997). Nature Struct.
Biol. 4, 269-275.
Weiss, M. S. & Hilgenfeld, R. (1997). J. Appl. Cryst.
30, 203-205.
Weiss, M. S. (2001). J. Appl. Cryst. 34, 130-135.
The R sym value as a decimal number.
Examples: null
Overall Chi-squared statistic.
An identifier for the diffraction data set for this set of summary statistics.
Multiple diffraction data sets entered as a comma separated list.
The ratio of the average intensity to the average uncertainty, /<sigma(I)>.
The mean of the ratio of the intensities to their standard uncertainties, <I/sigma(I)>.
Total number of measured reflections.
An ordinal identifier for this set of reflection statistics.
Overall redundancy for this data set.
Number of reflections rejected in scaling operations.
The percentage of geometrically possible reflections represented by reflections that satisfy the resolution limits established by _reflns.d_resolution_high and _reflns.d_resolution_low and the observation limit established by _reflns.observed_criterion.
The value of _reflns.phase_calculation_details describes a special details about calculation of phases in _refln.phase_calc.
Examples: From model, NCS averaging, Solvent flipping, Solvent flattening, Multiple crystal averaging, Multiple phase modification, Other phase modification
Generated using TypeDoc
The value of the overall isotropic displacement parameter estimated from the slope of the Wilson plot.