An inverse problem involving diffraction from disordered fibers

The inverse problem of determining the structure (atomic coordinates) of a helical molecule from measurements of the intensities of x-rays diffracted from a disordered, oriented, polycrystalline fiber of the molecule is considered., The problem is highly underdetermined, but can be solved by incorporating additional geometric and steric information. However, current solution methods, do not allow for disorder in the fiber specimen. A method for solving this problem for disordered fibers is described that utilizes current solution methods by iteratively modifying the diffraction data to account for the disorder. The method is successfully applied to diffraction data from a disordered DNA fiber.