Buy article online - an online subscription or single-article purchase is required to access this article.
research papers
Extinction effects in white-beam X-ray and neutron diffraction are considered following the formulation developed for monochromatic-beam diffraction by Becker & Coppens [Acta Cryst. (1974), A30, 129-147]. In white-beam diffraction, a small deviation of the wavelength from the Bragg condition Δλ is a variable which represents the line profile of the diffraction peaks, so that by using the new parameter Δλ the theory is converted to one in white-beam diffraction. It is shown that for a convex crystal, primary extinction yp agrees with the results calculated already for monochromatic diffraction. The same relation is shown to hold in secondary extinction ys. It is concluded that extinction theory derived for monochromatic diffraction is applicable without any modification in white-beam diffraction.