The probability distributions of X-ray intensities in fiber diffraction: largest likely values for fiber diffraction...

R factors in fiber diffraction are generally lower than in conventional crystallography, because of the cylindrical averaging of fiber diffraction data. The probability distributions for fiber diffraction intensities, analogous to Wilson's distributions for crystal diffraction intensities, are derived, and from these the largest likely values of R are estimated. These values depend on the size and symmetry of the diffracting particle and on the resolution of the analysis, and range from 0.586 for systems for very high symmetry (as in crystal diffraction) to much lower values for systems of low symmetry.