Reformulation of the dynamical theory of coherent wave propagation by randomly distorted crystals

The coherent terms in the spherical-wave approach of the statistical dynamical theory are reformulated using rigorous boundary conditions in contrast to the intuitive boundary conditions of the original formulation by Kato [Acta Cryst. (1980), A36, 763-769, 770-778]. These boundary conditions are explained physically by a general interference effect between the forward-diffracted wave and the incident undiffracted wave (using the optical theorem) and their consequences on the total (Bragg and forward-diffracted) incoherent intensity are also discussed.