Observation of strong two-electron--one-photon transitions in few-electron ion

Abstract

We resonantly excite the $K$ series of O${}^{5+}$ and O${}^{6+}$ up to principal quantum number $n=11$ with monochromatic x rays, producing $K$-shell holes, and observe their relaxation by soft-x-ray emission. Some photoabsorption resonances of O${}^{5+}$ reveal strong two-electron--one-photon (TEOP) transitions. We find that for the $[(1s2s{)}_{1}5p_{3/2}{]}_{3/2;1/2}$ states, TEOP relaxation is by far stronger than the radiative decay and competes with the usually much faster Auger decay path. This enhanced TEOP decay arises from a strong correlation with the near-degenerate upper states $[(1s2p_{3/2}{)}_{1}4s{]}_{3/2;1/2}$ of a Li-like satellite blend of the He-like $K\alpha$ transition. Even in three-electron systems, TEOP transitions can play a dominant role, and the present results should guide further research on the ubiquitous and abundant many-electron ions where electronic energy degeneracies are far more common and configuration mixing is stronger.

arXiv commentPublished in PRA

References in corpus (24)

• Observations of the MIssing Baryons in the warm-hot intergalactic medium
• Atomic Data for X-ray Astrophysics
• Soft X-Ray Absorption by Fe${}^{0+}$ to Fe${}^{15+}$ in Active Galactic Nuclei
• A Long Look at NGC 3783 with the XMM-Newton Reflection Grating Spectrometers
• The Athena X-ray Integral Field Unit (X-IFU)
• Characterizing the Warm-Hot IGM at High Redshift: A High Resolution Survey for O VI at z = 2.5
• The Heidelberg compact electron beam ion traps
• Polarization measurement of dielectronic recombination transitions in highly charged krypton ions
• Photoionization of ions with synchrotron radiation: From ions in space to atoms in cages
• Laboratory Measurement and Theoretical Modeling of K-shell X-ray Lines from Inner-shell Excited and Ionized Ions of Oxygen
• High Resolution Photoexcitation Measurements Exacerbate the Long-Standing Fe XVII Oscillator Strength Problem
• Theoretical energy levels of $1sns$ and $1snp$ states of helium-like ions
• Prominent role of multi-electron processes in K-shell double and triple photodetachment of oxygen anions
• Strong higher-order resonant contributions to x-ray line polarization in hot plasmas
• Multiple photodetachment of carbon anions via single and double core-hole creation
• Multipole (E1, M1, E2, M2) transition wavelengths and rates between states with n<= 6 in heliumlike carbon, nitrogen, oxygen, neon, silicon, and argon
• Complex scaled relativistic configuration-interaction study of the $LL$ resonances in helium-like ions: from Boron to Argon
• A practical theoretical formalism for atomic multielectron processes: direct multiple ionization by a single Auger decay or by impact of a single electron or photon
• Near--K-edge double and triple detachment of the F- negative ion: observation of direct two-electron ejection by a single photon
• Neon in ultrashort and intense x rays from free electron lasers
• Resonance strengths for KLL dielectronic recombination of highly charged mercury ions and improved empirical $\mathbf{Z}$-scaling law
• Line absorption of He-like triplet lines by Li-like ions. Caveats of using line ratios of triplets for plasma diagnostics
• The OVI mystery: mismatch between X-ray and UV column densities
• On the discrepancy between the X-ray and UV absorption measurements of OVI in the local ISM

Cited by in corpus (3)

• New Measurement Resolves Key Astrophysical Fe XVII Oscillator Strength Problem
• High-Precision Transition Energy Measurements of Neon-like Fe XVII Ions
• Detecting coherence with respect to general quantum measurements