Photoionization of Kr 4s. III. Detailed and extended measurements of the Kr 4s-electron ionization cross section

Abstract

Absolute Kr 4s-eJectron photoionization cross sections as a function of the exciting-photon energy were measured by photon-induced fluorescence spectroscopy (PIFS) at improved primary-energy resolution. The cross sections were determined from threshold to 33.5 eV and to 90 eV with primary-photon bandwidths of 25 meV and 50 meV, respectively. The measurements were compared with experimental data and selected theoretical calculations for the direct Kr 4s-eJectron photoionization cross sections.

Relativistic effects in photoionization time delay near the Cooper minimum of noble-gas atoms

“…Note that the energy regions around 27.48 eV (4s 1/2 threshold) and from 101.41 eV (3d 5/2 threshold) to 102.80 eV (3d 3/2 threshold) are skipped because they fall into the region of autoionization resonances. Comparison is made with the experimental data by Ehresmann et al [30] for 4s (displayed by filled circles with error bars), by Samson and Stolte [27] for the total 4s + 4p + 3d cross section (shown by open circles), and by Aksela et al [31] for 3d (displayed with asterisks). Good agreement between the two calculations can be seen for the 4p and 3d subshells which dominate the total cross section in their respective energy ranges.…”

“…More specifically, the sharp peak in the 4s time delay near the Cooper minimum of the partial photoionization cross section is shifted between the two calculations. [30] for 4s are displayed by filled circles with error bars and the total cross-section data by Samson and Stolte [27] are shown with open circles. The data from Aksela et al [31] for 3d are displayed with asterisks.…”

Raman Regime Energy Dependence of Alignment and Orientation of KrIi States Populated by Resonant Auger Effect

“…The experiment was carried out at the undulator beam line UE56/2-PGM2 of BESSY II, Berlin, using photon-induced fluorescence spectroscopy [21,22]. The energy of the exciting synchrotron radiation was varied in steps of 5 meV covering the energy range from resonance R2 to R4 whose energies are 92.425 and 92.560 eV, respectively [17].…”

Electron angular distributions of noble gases in sequential two-photon double ionization

“…In this context, Cooper-and correlative minima in the photoelectron partial cross sections are other important aspects regarding properties of the electronic structure and have been investigated for single-photon single ionization in the past [1]. Cooper-minima are known to arise from the decrease of the overlap integral of the bound and the continuum electronic state of the outgoing electron [24] whereas correlative minima are caused by the transition between correlation dominated photoelectron emission at lower energies and quasi-single electron emission at higher energies [25,26]. Reflections of these intensity variations along photon energy are also exhibited in the angular distribution of the photoelectron emission leading to a variation of the anisotropy parameter β.…”