Interpretation of dynamical diffuse scattering of fast electrons in rutile

An Einstein model for thermal diffuse scattering is extended to a fully dynamical n-beam Bloch-wave treatment, where explicit account is taken of the scattering site symmetry from individual atoms. Dynamical effects in this model are related to orientation-dependent fluctuations in current density on localized scattering centres within the crystal, yielding excess or deficit Kikuchi bands. Calculated diffuse scattering distributions are compared with experimental observations from rutile (TiO₂). The predicted diffuse distribution for scattering from oxygen sites correlates reasonably well with experiment, implying a relatively weak contribution for (localized) thermal diffuse scattering of fast electrons from titanium sites.