Solution of the phase problem in crystallography and application to dynamical electron diffraction.
Unitarity, a fundamental principle of scattering theory, leads to the prediction of an essentially unique set of phases for the scattering amplitude from a complete knowledge of the differential cross section or, in the case of a crystal, from the diffracted intensities. The Sayre equation and all the direct methods of phasing following there from are derived as a special case of unitarity for zero excitation error. Dynamical and kinematical scattering are considered, and the relationship between them, S = exp(i tau nzK), is obtained. Applications to the case of electron diffraction including for non-zero excitation error are discussed.
Tivol
W F
WF
Wadsworth Center for Laboratories and Research, School of Public Health, Albany, NY 12201-0509, USA.
D018360:Crystallography, X-Ray / Q000379:methods*; D004583:Electrons; D008432:Mathematical Computing; D012542:Scattering, Radiation