Phenomenological model of anisotropic peak broadening in powder diffraction
Journal of Applied Crystallography
Volume 32, Issue 2, pages 281–289, April 1999
How to Cite
Stephens, P. W. (1999), Phenomenological model of anisotropic peak broadening in powder diffraction. Jnl Applied Crystallography, 32: 281–289. doi: 10.1107/S0021889898006001
Anisotropic line-shape broadening (peak width which is not a smooth function of d-spacing) is frequently observed in powder diffraction patterns, and can be a source of considerable difficulty for whole-pattern fitting or Rietveld analysis. A model of the multi-dimensional distribution of lattice metrics within a powder sample is developed, leading naturally to a few parameters which can be varied to achieve optimal line-shape fits. Conditions on these parameters are derived for all crystal systems, and the method is illustrated with two examples: sodium p-hydroxybenzoate and rubidium fulleride.