Abstract
The authors introduce several techniques which are used in the X-ray crystallography phase retrieval problem and several unique problems associated with it. Phase retrieval involves signal reconstruction from its Fourier transform magnitude, which in this case is related to the X-ray diffraction pattern intensity. The following techniques are discussed: the isomorphic addition technique, the isomorphic replacement technique, and the multiple anomalous dispersion technique. Finally, a simulation result for the X-ray crystallography problem is presented.