Rayleigh scattering of X-ray and γ-ray by 2p electrons in ions and neutral atoms

Abstract

Analytical formulae for the nonrelativistic 2p subshell Rayleigh scattering amplitudes and cross section are obtained using the second order S-matrix element and the Coulombian Green function method, including multipoles and retardation. Relativistic kinematics effects are taking into account, allowing to remove the spurious poles that occur in a usual nonrelativistic calculation with retardation included. The nonrelativistic limit is obtained by removing the relativistic higher order terms in ω/m. A simple formula is also obtained for the total photoeffect cross section for a 2p electron. In the realistic case of ionized and neutral atoms, the screening effects were included by using an effective charge Z eff approach. A good agreement within 10% is found when comparing the predictions given by our analytical results for total photoionization cross section with the full relativistic numerical calculations in the case of 2p subshell for neutral atoms with 26 ≤ Z ≤ 92 and photon energies up to 100 keV.