Rietveld refinement of Y₂O₃ using the Pearson VII profile shape function

Abstract

Abstract Very good agreement between the observed and the calculated intensities was obtained using the Pearson VII profile shape function. The variable exponent m could be refined only in the damped iterations involving exclusively the profile parameters. Simultaneous refinement of the m with the positional and/or thermal parameters has led to large oscillations of the shifts of almost all parameters. Precision of the refined atomic coordinates is better than those from previously published Rietveld refinement and is comparable with single crystal results. The degree of serial correlation in residuals has been determined by the use of the Durbin‐Watson d statistic. Normal probability plot based on δ R i has been almost linear with the slope greater than one. The weighting scheme with w i = 1/ y oi has proved to be good first approximation.