Bremsstrahlung of relativistic particles and dynamic polarizability of target atom

The bremsstrahlung emitted during the collision of a relativistic charged particle with a complex atom is analyzed. The target atom is treated as a dynamic system having internal degrees of freedom. The basic characteristics of the emission are derived for photon frequencies on the order of the ionization potential of the atom. These characteristics are the spectrum of the emitted photons, the angular distributions of the electromagnetic radiation and of the scattered particles, and the polarization of the radiation. The bremsstrahlung cross section that is differential with respect to the photon energy increases logarithmically with the energy of the incident particle