The influence of profile analysis on structural parameters and deformation density distributions

Nett X-ray diffraction intensities have been determined from measured step-scan profiles of deuterated 2,5- dimethyl-3-hexyne-2,5-diol by four different profile analysis procedures. Least-squares refinements based on the different sets of F values showed that variations in profile analysis method may change the coordinates by 1.5 times the σ of 0.8 x 10^-4 Å and the thermal parameters by twice the σ of 1.4 x 10^-5 Ų. The change in scale factor is 1.2% or 4σ. A correct choice of refinement procedure, in which full-angle data are used for the determination of the scale, turned out to be more important for the calculation of reliable deformation densities than the choice of profile-analysis method.