Single and doubleK-shell ionization and electron-transfer cross sections for Fe and Ni bombarded by S ions and Fe by Si ions at 1.25–4.70 MeV/amu

Abstract

Single and double K-shell vacancy production and K-K electron-transfer cross sections have been measured in the limit of zero target thickness for Fe and Ni induced by 1.25--4.70 MeV/amu $^{28}\mathrm{Si}$ and $^{32}\mathrm{S}$ ions. The fluorescence yield ${\mathrm{\ensuremath{\omega}}}_{\mathit{k}}$ for Fe and Ni at x-ray emission was determined from the measured energy shifts of target K x rays, the intensity ratios of K\ensuremath{\beta} and K\ensuremath{\alpha} and using the statistical scaling procedure of Larkins [J. Phys. B 4, L29 (1971)]. The single-electron-transfer cross sections are compared with the atomic-orbital-expansion model (AO) of Fritsch and Lin [Phys. Rep. 202, 1 (1991)], and the semiempirical perturbed-stationary-state (PSS) approach of Lapicki and McDaniel [Phys. Rev. A 22, 1896 (1980)]. The AO calculations show excellent agreement with the single K-K transfer cross sections. This model also explains the double K-K transfer data quite well although it underestimates slightly the measured values. The direct K-shell ionization cross section data are compared with the ECPSSR (perturbed-stationary-state theory with energy-loss, Coulomb deflection, and relativistic corrections) calculations.