Quantum theory of inelastic scattering of negatively charged particles in oriented crystals

The effect of interaction between a relativistic electron and the phonon and electron excitations of a crystal on the stability of motion in an axial or plane channel is investigated within the framework of the general quantum approach. It is shown that the widely accepted concept of electron channeling as a quasiperiodic motion involving a comparatively slow 'diffusion' of the particle in transverse energy and momentum space is invalid. For electron energies exceeding several tens (for the axis) or hundreds (for the plane) MeV channeling in this sense does not exist. For electrons of lower energy, and also for heavy nega tively charged particles with energies exceeding several hundreds GeV, the quantum and classical expressions respectively are obtained for the quantities characterizing the dechanneling process