Prominent role of multi-electron processes in K-shell double and triple photodetachment of oxygen anions

Abstract

The photon-ion merged-beams technique was used at a synchrotron light source for measuring absolute cross sections of double and triple photodetachment of O${}^{-}$ ions. The experimental photon energy range of 524-543 eV comprised the threshold for K-shell ionization. Using resolving powers of up to 13,000, the position, strength and width of the below-threshold 1s 2s2 2p6 2S resonance as well as the positions of the 1s 2s2 2p5 3P and 1s 2s2 2p5 1P thresholds for K-shell ionization were determined with high precision. In addition, systematically enlarged multi-configuration Dirac-Fock calculations have been performed for the resonant detachment cross sections. Results from these ab-initio computations agree very well with the measurements for the widths and branching fractions for double and triple detachment, if double shake-up (and -down) of the valence electrons and the rearrangement of the electron density is taken into account. For the absolute cross sections, however, a previously found discrepancy between measurements and theory is confirmed.

arXiv comment5 pages, 2 figures

References in corpus (4)

• Absolute cross sections for photoionization of Xe${}^{q+}$ ions (1 $\le$ q $\le$ 5) at the 3d ionization threshold
• Photoionization of ions with synchrotron radiation: From ions in space to atoms in cages
• High Precision {\it K}-Shell Photoabsorption Cross Sections for Atomic Oxygen: Experiment and Theory
• Threshold photodetachment in a repulsive potential

Cited by in corpus (14)

• Near L-Edge Single and Multiple Photoionization of Singly Charged Iron Ions
• Photoionization of metastable heliumlike C4+(1s 2s 3S1) ions: Precision study of intermediate doubly excited states
• Near L-edge photoionization of triply charged iron ions
• Multiple photodetachment of carbon anions via single and double core-hole creation
• Near-K-edge single, double, and triple photoionization of C+ ions
• The photon-ion merged-beams experiment PIPE at PETRAIII - The first five years
• Near L-Edge Single and Multiple Photoionization of Doubly Charged Iron Ions
• Near--K-edge double and triple detachment of the F- negative ion: observation of direct two-electron ejection by a single photon
• Observation of strong two-electron--one-photon transitions in few-electron ion
• Photoionization of astrophysically relevant atomic ions at PIPE
• Multiple photodetachment of atomic anions via single and double core-hole creation
• Near K-Edge Photoionization and Photoabsorption of Singly, Doubly, and Triply Charged Silicon Ions
• Multiple photodetachment of silicon anions via K-shell excitation and ionization
• Multiple Photodetachment of Oxygen Anions via K-Shell Excitation and Ionization: Direct Double-Detachment Processes and Subsequent Deexcitation Cascades