Hollow ion atomic structure and X-ray emission in dense hot plasmas

Hollow ion X-ray emission is of great interest in high-energy-density research, since negligible opacity allows studies from the interior of very dense objects. In this paper, ionization potential depressions of the isoelectronic sequences for single and double K-shell vacancies are obtained from a pure ab initio multiconfiguration Hartree–Fock simulation including exact exchange terms and finite temperature dense plasma effects. It is demonstrated that the simultaneous representation of these ab initio data in the form of a map of hollow ion X-ray transition energies enables identification of important steps in the matter evolution and ionization dynamics. Mapping along the isoelectronic sequence as a function of the pumping energy of a X-ray free electron laser also enables visualization of the impact of ionization potential depression on the pathways of hollow ion formation.