Calculation of powder-pattern intensity distributions

If spherical crystals are assumed, and a Patterson function which is averaged over all orientations is used, it is possible to obtain a simple expression for the intensity distribution in a powder pattern. Unlike the Debye equation, which is useful only for extremely small crystals, the present equation is practical no matter how large the crystals. As two examples, powder patterns are calculated for crystals containing 67 atoms and 536 atoms.