Diffraction pattern of crystals with numerous stacking faults

A model for crystals with stacking faults is given; it takes account of interaction up to the vth neighbor; it is reduced to a first-order Markov chain. It is shown that the diffraction pattern can be split into spots, the shape of which depends on three parameters (intensity, width, 'asymmetry'). Group theory is used. Application is given for hexagonal-rhombohedral stacking faults (as in graphite) for interactions up to third order.