Photoionization of Ar and Ar-like ions near the 3s-threshold

Abstract

The absolute cross sections for the 3s-photoionization and the 3p-photoionization of the Ar atom and the Ar-like ions K+ and Ca2+ are calculated. The calculation is performed within the configuration-interaction technique using the Pauli-Fock atomic orbitals. The simultaneous analysis of the calculated and measured total and partial cross sections yields the interpretation of the prominent resonances observed in a recent experiment on Ar above the 3s-threshold.

New Window Resonances in the Potassium 3sPhotoabsorption Spectrum

“…However, their appearance is in contrast to the Ar 3s → np spectrum, which shows a very sharp and regular Rydberg series 11 up to high n. The potassium resonances are broader with a less clear Rydberg series structure, disappearing at lower n. This is true not only for neutral potassium atoms but also for potassium ions as observed previously. [18][19][20][21] Since K + is isoelectronic to Ar, it can be inferred that the presence of a valence 4s electron does not play a decisive role in this difference. However, the most striking feature of the K + yield spectrum is a paired windows structure, with the deepest and lowest feature at 36.7 eV and a smaller one right next to it at 37.4 eV, clearly too close to be the next member of the Rydberg series.…”

“…In particular, the subvalence s-shell photoexcitation in rare gas atoms [5][6][7][8][9][10][11][12][13][14][15] and closely related species [18][19][20][21] have been noted for the window type resonances, appearing as dips in the continuum background of the photo-absorption spectrum. Window resonances are extreme cases of the Beutler-Fano profile with profile index q close to zero.…”

Variation of 3sPhotoionization Resonance Structures in a Serial Atomic Number Species Ar, K, and Ca

“…np excitations of Ar isoelectronic sequence, a dramatic change of the resonance shape along with the change of atomic number has been reported. [12][13][14][15] In a previous paper, we reported the window resonances of heavier alkaline atoms K, 16) Rb, and Cs. 17) The window resonance of these species were found to be distinctively broader compared with their neighboring rare gas atoms.…”

Many-electron dynamics of atomic processes studied by photon-induced fluorescence spectroscopy

“…Amusia et al (1970) have extended the RPA ap- Amusia et al (1974) with experimental data (Samson and Cairns, 1968;Lynch et al, 1973;Samson and Gardner, 1974). Insert shows the partial terms of the transition amplitude computed in CIPF approach by Lagutin et al (1999). proach of Altick and Glassgold (1964) by using the HF AOs computed with exchange which is called the RPAE approach.…”