Strain distributions and diffraction peak profiles from crystals with dislocations

Diffraction profiles for different models of dislocation arrangements are calculated directly by the Monte Carlo method and compared with the strain distributions for the same arrangements, which corresponds to the Stokes-Wilson approximation. It is shown that the strain distributions and the diffraction profiles are in close agreement as long as long-range order is absent. Analytical calculation of the strain distribution for uncorrelated defects is presented. For straight dislocations, the Stokes-Wilson and the Krivoglaz-Wilkens approximations give the same diffraction profiles, with the Gaussian central part and proportional to q(-3) power law at the tails. (C) 2014 International Union of Crystallography