Relativistic convergent close-coupling method: Calculation of electron scattering from hydrogenlike ions

Abstract

We report on the extension of the recently formulated relativistic convergent close-coupling (RCCC) method to include the Breit and M\o{}ller interactions. The inclusion of these relativistic effects ensures that the RCCC method is now capable of calculating electron scattering excitation and ionization cross sections for highly charged ions. We have calculated the polarization of the Lyman-${\ensuremath{\alpha}}_{1}$ x-ray line emitted by hydrogenlike ${\text{Ti}}^{21+}$, ${\text{Ar}}^{17+}$, and ${\text{Fe}}^{25+}$ ions excited by electron impact. We find that account of Breit relativistic corrections is important to resolve the discrepancy between experiment and theoretical calculations. For the much heavier hydrogenlike ${\text{U}}^{91+}$ ion where the M\o{}ller interaction becomes important we present the estimate of the polarization of the Lyman-${\ensuremath{\alpha}}_{1}$ x-ray line and performed a calculation of the total ionization cross section.