differential cross section for the resonant scattering of a linearly polarized X-ray photon by a free xenon atom
near the K-shell ionization threshold has been theoretically analyzed. The evolution of the spatially extended
structure of the scattering cross section to the K
,
structure of the X-ray spectrum of the xenon atom emission has been demonstrated. The calculations have been performed in the dipole approximation for the anomalous
dispersion component of the total inelastic scattering amplitude and in the impulse approximation for the con-
tact component of this amplitude. The contribution of the Rayleigh (elastic) scattering component is taken into
account using the methods developed in Hopersky et al., J. Phys. B 30, 5131 (1997). The effects of the radial
relaxation of the electron shells, spin–orbit splitting, double excitation/ionization of the atomic ground state, as
well as the Auger and radiative decays of the produced main vacancies, are considered. Using the results
obtained by Tulkki, Phys. Rev. A 32, 3153 (1985) and Biggs et al., At. Data Nucl. Data Tables 16, 201 (1975),
the nonrelativistic Hartree–Fock wavefunctions are changed to the relativistic Dirac– Hartree–Fock wavefunc-
tions of the single-particle scattering states when constructing the process probability amplitude. The calcula-
tions are predicting and are in good agreement with the synchrotron experiment on the measurement of the
absolute values and shape of the double differential cross section for the resonant scattering of an X-ray photon
by a free xenon atom reported by Czerwinski et al., Z. Phys. A 322, 183 (1985).