Many-electron effects on the x-ray Rayleigh scattering by highly charged He-like ions

TL;DR

This paper develops a quantum electrodynamics-based perturbation theory to analyze many-electron effects in x-ray Rayleigh scattering by highly charged helium-like ions, revealing effects beyond the independent-particle approximation are minimal at high energies.

Contribution

It introduces a rigorous quantum electrodynamics approach to evaluate many-electron effects in Rayleigh scattering, extending beyond the independent-particle approximation.

Findings

Many-electron effects are less than 2% for high-energy photons.

The approach is applied to Ni$^{26+}$, Xe$^{52+}$, and Au$^{77+}$ ions.

Effects beyond IPA are negligible for closed K-shells at high energies.

Abstract

The Rayleigh scattering of x-rays by many-electron highly charged ions is studied theoretically. The many-electron perturbation theory, based on a rigorous quantum electrodynamics approach, is developed and implemented for the case of the elastic scattering of (high-energetic) photons by helium-like ion. Using this elaborate approach, we here investigate the many-electron effects beyond the independent-particle approximation (IPA) as conventionally employed for describing the Rayleigh scattering. The total and angle-differential cross sections are evaluated for the x-ray scattering by helium-like Ni$^{26+}$, Xe$^{52+}$, and Au$^{77+}$ ions in their ground state. The obtained results show that, for high-energetic photons, the effects beyond the IPA do not exceed 2% for the scattering by a closed $K$-shell.