Resonance inelastic scattering of an x-ray photon by the xenon atom

The effect of many-particle and relativistic effects on the absolute values and the shape of the doubly differential cross section of resonance inelastic scattering of a linearly polarized x-ray photon by the free xenon atom in the energy region of the K ionization threshold is studied theoretically. The evolution of the spatially extended structure of the scattering cross section in the Kα,β structure of the x-ray emission spectrum of the xenon atom is demonstrated. The calculations were performed in the dipole approximation for the anomalous dispersion part of the total amplitude of probability of inelastic scattering and in the impulse approximation for the contact part of this amplitude. The radial relaxation of electronic shells, the spin-orbit splitting, the double excitation/ionization of the ground atomic state, as well as the Auger and radiative decays of the atomic core vacancies being formed were taken into account. In constructing the probability amplitude of the process, the relativistic effects were taken into account as a passage from the nonrelativistic Hartree-Fock wave functions to the relativistic Dirac-Hartree-Fock wave functions of the one-particle scattering states and as the passage (for the radiative transition amplitudes) to the relativistic form of the operator of the photon-atom interaction. The calculation results are predictive in character and, at the incident photon energy 34.42 keV, agree well with the results of the synchrotron experiment.