Simultaneous loss and excitation of projectile electrons in relativistic collisions of U$^{90+}$(1s$^2$) ions with atoms

TL;DR

This paper investigates a complex two-electron process in relativistic uranium ion collisions, demonstrating that advanced models significantly improve the accuracy of calculated cross sections for electron excitation and loss.

Contribution

It introduces the use of relativistic symmetric eikonal and continuum-distorted-wave-eikonal-initial-state models for better cross section calculations in a four-body relativistic collision problem.

Findings

Significant improvement in cross section calculations with advanced models.

Validation of the independent electron model in relativistic collisions.

Enhanced understanding of electron excitation and loss mechanisms.

Abstract

We study relativistic collisions between helium-like uranium ions initially in the ground state and atoms in which, in a single collision event, one of the electrons of the ion is emitted and the other is transferred into an excited state of the residual hydrogen-like ion. We consider this two-electron process at not very high impact energies, where the action of the atom on the electrons of the ion can be well approximated as occurring solely due to the interaction with the nucleus of the atom and, hence, the process can be regarded as a four-body problem. Using the independent electron model we show that a very substantial improvement in the calculated cross sections is obtained if, instead of the first order approximation, the relativistic symmetric eikonal and continuum-distorted-wave-eikonal-initial-state models are employed to describe the single-electron probabilities for the excitation and loss, respectively.