SCRAP - a computer program for the analysis of powder diffraction patterns

A new computer program (SCRAP) for the analysis of powder diffraction patterns is described. A least-squares fitting of the observed and calculated intensities for individual points on the diffraction profile is used to determine values for the integrated intensities of the peaks, as well as any specified profile parameters. Conventional least-squares analysis of the integrated intensities can then be used to refine the values of the structural parameters. Use of this program therefore overcomes the limitations of the Rietveld profile refinement program (Rietveld. Acta Cryst.; 22: 151 (1967) and J. Appl. Cryst.; 2: 65 (1969)), in particular the unreliability of the estimated standard deviation values given by the latter. (author)