Method of analyzing powder diffraction data in which the crystal structure is refined by fitting the entire profile of the diffraction pattern to a calculated profile using a least-squares approach. There is no intermediate step of extracting structure factors, and so patterns containing many overlapping Bragg peaks can be analyzed.
The method was applied originally by H. Rietveld [(1967). Acta Cryst. 22, 151–152. Line profiles of neutron powder diffraction peaks for structure refinement; (1969). J. Appl. Cryst. 2, 65–71. A profile refinement method for nuclear and magnetic structures] to the refinement of neutron intensities recorded at a fixed wavelength. Subsequently, it has been used successfully for analyzing powder data with neutrons or X-rays as the primary radiation and with scattered intensities measured at a fixed wavelength (and variable scattering angle) or at a fixed scattering angle (and variable wavelength).
The Rietveld method. A. Albinati and B. T. M. Willis. International Tables for Crystallography (2006). Vol. C, ch. 8.6, pp. 710-712 doi:10.1107/97809553602060000614
The Rietveld Method, edited by R.A. Young. (1993), Oxford: IUCr/Oxford University Press.