State-resolved valence shell photoionization of Be-like ions: experiment and theory

Müller, Alfred; Schippers, S.; Phaneuf, R. A.; Kilcoyne, A. L. D.; Bräuning, H.; Schlachter, A. S.; Lu, Mei-Ju; McLaughlin, B. M.

doi:10.1088/0953-4075/43/22/225201

Cited by 21 publications

(28 citation statements)

References 48 publications

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“…This is supported by the findings in level-resolved photoionization experiments with ground-level and metastable excited beryllium-like ions (Müller et al 2010b). Considering the ion flight time of the order of 40μs between the ion source and the interaction region of the present experiment, the initial population does not change significantly prior to the measurement.…”

Section: Resonance Parameters and Decay Probabilitiessupporting

confidence: 88%

Photoionization of Ne Atoms and Ne⁺ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

Müller

Bernhardt

Borovik

et al. 2017

ApJ

114

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Single, double, and triple photoionization of Ne + ions by single photons have been investigated at the synchrotron radiation source PETRA III in Hamburg, Germany. Absolute cross-sections were measured by employing the photon-ion merged-beams technique. Photon energies were between about 840 and 930 eV, covering the range from the lowest-energy resonances associated with the excitation of one single K-shell electron up to double excitations involving one K-and one L-shell electron, well beyond the K-shell ionization threshold. Also, photoionization of neutral Ne was investigated just below the K edge. The chosen photon energy bandwidths were between 32 and 500 meV, facilitating the determination of natural line widths. The uncertainty of the energy scale is estimated to be 0.2 eV. For comparison with existing theoretical calculations, astrophysically relevant photoabsorption cross-sections were inferred by summing the measured partial ionization channels. Discussion of the observed resonances in the different final ionization channels reveals the presence of complex Auger-decay mechanisms. The ejection of three electrons from the lowest K-shell-excited Ne + ( s s p 1 2 2 S 2 6 2 1 2 ) level, for example, requires cooperative interaction of at least four electrons.

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Section: Resonance Parameters and Decay Probabilitiessupporting

confidence: 88%

Photoionization of Ne Atoms and Ne⁺ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

Müller

Bernhardt

Borovik

et al. 2017

ApJ

114

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“…Indeed, the resonance strength of the 1 P o resonance populated from the ground state of B + would go up with the assumption of a 29% metastable fraction by almost 20%, however, the good agreement found for the other two resonances would be spoiled. Moreover, it was discussed recently on the basis of detailed studies on Belike ions [67] energy scans covering the whole energy range from 193.7-194.7 eV their relative heights are very well determined by the experiment, the partial discrepancy between the present theory and the experimental data cannot be removed by assuming different values for the metastable fraction of ions in the parent beam. Figure 3 addresses a second energy range (from about 209-215 eV) that was investigated in the present experiments.…”

Section: Photoionizationmentioning

confidence: 80%

K-shell photoionization of Be-like boron (B⁺) ions: experiment and theory

Müller¹,

Schippers²,

Phaneuf³

et al. 2014

J. Phys. B: At. Mol. Opt. Phys.

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View the article online for updates and enhancements. AbstractAbsolute cross sections for the K-shell photoionization of Be-like boron ions were measured with the ion-photon merged-beams technique at the Advanced Light Source synchrotron radiation facility. High-resolution spectroscopy with E/ E up to 8800 ( E ∼ 22 meV) covered the energy ranges 193.7-194.7 eV and 209-215 eV. Lifetimes of the strongest resonances are determined with relative uncertainties down to approximately 4% for the broadest resonance. The measured resonance strengths are consistent with 60% 1s 2 2s 2 1 S ground-state and 40% 1s 2 2s2p 3 P o metastable-state ions in the primary ion beam and confirmed by comparison with independent absolute photo-recombination heavy-ion storage-ring measurements with B 2+ ions using the principle of detailed balance. Experimental determination of the line width for the 1s2s 2 2p 1 P o resonance gives a value of 47 ± 2 meV and compares favourably to a theoretical estimate of 47 meV from the R-matrix with pseudo-states (RMPS) method. The measured line widths of the 1s2s2p 2 3 P, 3 D resonances are 10.0 ± 2 meV and 32 ± 3 meV, respectively, compared to RMPS theoretical estimates of 9 meV and 34 meV.

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“…The advent of third-generation synchrotron radiation sources (3GLS) with insertion devices increased the photon beam intensities available to experimenters by nearly three orders of magnitude, making possible the study of photoionization of ions with unprecedented sensitivity and spectral resolution. This has permitted measurements with ions of the lighter and more astrophysically abundant elements, e.g., C + [17], O + [18,19], C 2+ [20], and more recently C 3+ [21] and N 3+ and O 4+ [22], which are helping to refine theoretical descriptions of the photoionization process.…”

Section: Introductionmentioning

confidence: 99%

Valence-shell photoionization of chlorinelike Ar+ions

et al. 2011

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Absolute cross-section measurements for valence-shell photoionization of Ar + ions are reported for photon energies ranging from 27.4 to 60.0 eV. The data, taken by merging beams of ions and synchrotron radiation at a photon energy resolution of 10 meV, indicate that the primary ion beam was a statistically weighted mixture of the 2 P o 3/2 ground state and the 2 P o 1/2 metastable state of Ar + . Photoionization of this Cl-like ion is characterized by multiple Rydberg series of autoionizing resonances superimposed on a direct photoionization continuum. Observed resonance line shapes indicate interference between indirect and direct photoionization channels. Resonance features are spectroscopically assigned and their energies and quantum defects are tabulated. The measurements are satisfactorily reproduced by theoretical calculations based on an intermediate coupling semirelativistic Breit-Pauli approximation.

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State-resolved valence shell photoionization of Be-like ions: experiment and theory

Cited by 21 publications

References 48 publications

Photoionization of Ne Atoms and Ne⁺ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

Photoionization of Ne Atoms and Ne⁺ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

K-shell photoionization of Be-like boron (B⁺) ions: experiment and theory

Valence-shell photoionization of chlorinelike Ar+ions

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State-resolved valence shell photoionization of Be-like ions: experiment and theory

Cited by 21 publications

References 48 publications

Photoionization of Ne Atoms and Ne+ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

Photoionization of Ne Atoms and Ne+ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

K-shell photoionization of Be-like boron (B+) ions: experiment and theory

Valence-shell photoionization of chlorinelike Ar+ions

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Product

Resources

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Photoionization of Ne Atoms and Ne⁺ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

Photoionization of Ne Atoms and Ne⁺ Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

K-shell photoionization of Be-like boron (B⁺) ions: experiment and theory