Resonant scattering and multiple Bragg X-ray diffraction in LaMnO3; a classical view
The mechanism for resonant scattering in LaMnO
3 has been the subject of some controversy between two competing models, leading to different
d-electron densities. Forbidden reflections like 300 and 10-4 are turned on by resonance. Three-beam diffraction can be used to resolve ambiguities in determining valence electron densities obtained by means of resonant scattering. The choice between a negative and a positive structure factor is a particular aspect of the phase problem for which the technique of three-beam diffraction is particularly suited.
R. Colella and Q. Shen