Domain size anisotropy in the double-Voigt approach: an extended model

An efficient geometric approach to refine anisotropic domain morphology in the double-Voigt approach based on the variance-slope apparent crystallite size was recently described. In this way, the Lorentzian part of the Voigt size contribution can be directly linked to an effective area- or surface-weighted morphology. The size contribution in the Voigt approach is, however, rarely pure Lorentzian. In this article, the previously considered models are extended for the Gaussian part of the size broadening, also taking into account size distributions. The limits of the validity of the Voigt approach are also discussed.