FAULTS is a program that allows you to refine the X-Ray Powder Diffraction (XRD) and Neutron Powder Diffraction (NPD) patterns of crystal systems with any type of coherent planar defect.

The program is based on the CrysFML (Crystallographic Fortran Modules Library) and the DIFFaX (Diffracted Intensities From Faulted Xtals) program.

The DIFFaX program enables calculating the diffraction intensities of the defective layered crystals offering merely qualitative results. However, sometimes these data are not sufficient for a thorough microstructural characterization.

FAULTS, on the other hand, enables to perform refinements of experimental powder patterns (i.e. a computerized comparison of the intensities calculated by DIFFaX with experimental data), as well as allows, as DIFFaX does, the simulation of 2D diffraction patterns and diffuse streaks in the reciprocal space for single crystals.

Last version

The latest version of the FAULTS program includes a number of remarkable new features, such as the use of the Levenberg-Marquard Minimization Algorithm (LMA) which allows to speed up considerably the calculation time.

Other useful new features are the visualization of the model structures with FullProf Studio and VESTA, the possibility to include the diffracted intensities of the secondary phases as background, the refinement of the background points when treated as polynomial or the automatic conversion of the DIFFaX input files into FAULTS format using the DIFFaX2FAULTS converter.

The program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY of being free of internal errors. In no event shall the authors (or their institutions) be liable for any damages, including any general, special, incidental, or consequential damages arising out of the use or inability to use the programs.

Related articles

About the program itself:

  • Casas-Cabanas M., Reynaud M., Rikarte J., Horbach P., Rodríguez-Carvajal J., J. Appl. 49, 2016. DOI: 10.1107/S1600576716014473 (an authorised electronic reprint is available for FAULTS users in our Downloads section).
  • FAULTS, a new program for refinement of powder diffraction patterns from layered structures. Casas-Cabanas M., Rodríguez-Carvajal J. and Palacín M.R. Z. Kristallogr. Suppl., 23:243-248, 2006. DOI: 10.1524/9783486992526-042 (article in open access).
  • A general recursion method for calculating diffracted intensities from crystals containing planar faults. Treacy M.M.J., Newsam J.M. and Deem M.W. Proc. R. Soc. Lond. A, 433:499-520, 1991. DOI: 10.1098/rspa.1991.0062.

Examples of studies of battery materials using the program FAULTS:


  • Montse Casas-Cabanas (CIC energiGUNE)
  • Marine Reynaud (CIC energiGUNE)
  • Jokin Rikarte (CIC energiGUNE)
  • Pavel Horbach (Institut Laue Langevin)
  • Juan Rodríguez-Carvajal (Institut Laue Langevin)



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