A density matrix formulation of the dynamical theory of spectral shifts from correlated lattice vibrations in electron channeled radiation is presented. For lower-energy channeling, in which two bound levels exist in the channeling potential, positive shifts can be demonstrated. In the case of higher-energy channeling, where the number of bound levels increases, reduced positive shifts and negative shifts are shown. The theory suggests a novel method for experimentally determining a transverse, vibration correlation length in crystals.

• Received 16 March 1984

DOI:https://doi.org/10.1103/PhysRevLett.55.406