From Online Dictionary of Crystallography
Méthode de Rietveld (Fr).
Method of analysing 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 analysed.
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 analysing 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.