X-ray-photon scattering by an excited and ionized atom

The scattering process of an x-ray photon by an excited and ionized many-electron atom with attosecond photon-electron contact interaction is theoretically investigated. The results of the authors' recentwork [Hopersky et al., Phys. Rev. A 88, 032704 (2013)] are generalized for the cases of (a) arbitrary energy of the photon that prepares the scattering state and (b) the scattering of the photon by the continuous spectrum electron of the ionization state of the atom. The atom of Ne is considered as the object of the study. Along with the effects of normal Compton and elastic scattering, the existence of anomalous inelastic scattering is predicted. It may be assumed that this effect will become a basis for an experimental method of increasing the energy of the photons generated, for example, by a free-electron x-ray laser. It is determined that during the elastic scattering of a photon by an electron of the continuous spectrum, along with the known contribution from the j(l) Bessel function over the l = 0 harmonic (Thomson scattering), there is also a contribution from Bessel functions with harmonics l is an element of [1;infinity). The experimental discovery and application of the anomalous Compton photon scattering effect directly by the atomic electron of the continuous spectrum have their own practical interest.