Measurements of absolute photoionisation cross sections of Ca<sup>+</sup>ions

Lyon, I. C.; Peart, B; Dolder, K T; West, John B.

doi:10.1088/0022-3700/20/7/015

Cited by 68 publications

(69 citation statements)

References 8 publications

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“…The PI calculations for ground-level Ca + (3p 6 4s 2 S 1/2 ) ions can be compared with and benchmarked by the absolute measurements carried out by Lyon et al [33]. Their experimental PI spectrum was measured at a resolution of 32 meV.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, shorter energy ranges were scanned at higher resolution, including bandpasses of 8.8 meV, 4.6 meV, and 3.3 meV. Because of the availability of absolute cross sections for PI of Ca + in smaller energy regions and at lower resolving powers [33,36] no attempt was made to carry out absolute measurements in the present study. The focus was rather on well calibrated photon energies and high-resolution spectroscopy of autoionizing levels in the Ca + ion.…”

Section: Beams Of Camentioning

confidence: 99%

“…Following the work of Miecznik et al [39], calculations by Ivanov and West [40], using the non-relativistic, spin polarized version of the random-phase approximation with exchange (RPAE), determined positions and intensities of the resonances seen experimentally in the PI spectrum of Ca + in the range 27 -43 eV [33]. Values for the oscillator strengths and energy positions for the main one-electron transitions were obtained, and this information was used to tentatively identify the most prominent features in the experimental spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Photoionisation of Ca⁺ions in the valence-energy region 20–56 eV: experiment and theory

Müller

Schippers

Phaneuf

et al. 2017

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

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Abstract. Relative cross sections for the valence shell photoionisation (PI) of 2 S ground level and 2 D metastable Ca + ions were measured with high energy resolution by using the ion-photon merged-beams technique at the Advanced Light Source. Overview measurements were performed with a full width at half maximum bandpass of ∆E = 17 meV, covering the energy range 20 eV -56 eV. Details of the PI spectrum were investigated at energy resolutions reaching the level of ∆E = 3.3 meV. The photon energy scale was calibrated with an uncertainty of ±5 meV. By comparison with previous absolute measurements the present experimental high-resolution data were normalised to an absolute cross-section scale and the fraction of metastable Ca + ions that were present in the parent ion beam was determined to be 18±4%. Large-scale R-matrix calculations using the Dirac Coulomb approximation and employing 594 levels in the close-coupling expansion were performed for the Ca + (3s 2 3p 6 4s 2 S 1/2 ) and Ca + (3s 2 3p 6 3d 2 D 3/2,5/2 ) levels. The experimental data are compared with the results of these calculations and previous theoretical and experimental studies.

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Section: Resultsmentioning

confidence: 99%

Section: Beams Of Camentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photoionisation of Ca⁺ions in the valence-energy region 20–56 eV: experiment and theory

Müller

Schippers

Phaneuf

et al. 2017

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

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“…In order to evaluate numerically expression ͑2͒ for any given NL we use the measured experimental resonance photoionization cross section of Ca ϩ . 19 Since the reciprocal linear dispersion of the 0.2 m spectrometer was 4 nm/mm and we were operating with a 250 m exit slit, the interval ⌬E was 0.89 eV, which in turn sets the limits of the integration. Finally I 0 (E) is approximately constant over the interval ⌬E and hence the expression for the equivalent width simplifies to…”

Section: ͑2͒mentioning

confidence: 99%

“…In particular, Ca ϩ was chosen since its absolute VUV cross section has been measured 19 which permitted us to construct a column density map of Ca ϩ in the plasma plume. We have also been able to track in time and extract the expansion velocity of the Ca ϩ component of the plume, which turns out to be in good agreement with the model of Singh and Narayan.…”

Section: Introductionmentioning

confidence: 99%

Vacuum-ultraviolet resonant photoabsorption imaging of laser produced plasmas

Hirsch

Meighan

Mosnier

et al. 2000

Journal of Applied Physics

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We present results from a vacuum-ultraviolet ͑VUV͒ ''photoabsorption imaging'' technique based on the measurement of the time and space resolved absorption of a quasimonochromatic VUV beam from a laser plasma light source. The use of VUV radiation as a probe beam permits direct access to resonance lines of ͑singly and more highly charged͒ ions and also to the resonant and nonresonant continua of atoms and ions. In this experiment we have confined ourselves to measurements using the 3p -3d resonances of Ca, Ca ϩ , and Ca 2ϩ as markers of the temporal and spatial distribution of ground state atoms and ions in an expanding laser plasma plume. We show how time resolved column density maps may be extracted from such images. In addition we have extracted plasma plume velocities from the data, which compare well with an analytical laser ablation model.

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The photon‐ion merged‐beams experiment PIPE at PETRA III—The first five years

et al. 2019

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The Photon-Ion Spectrometer at PETRA III -in short, PIPE -is a permanently installed user facility at the "Variable Polarization XUV Beamline" P04 of the synchrotron light source PETRA III operated by DESY in Hamburg, Germany. The careful design of the PIPE ion-optics in combination with the record-high photon flux at P04 has lead to a breakthrough in experimental studies of photon interactions with ionized small quantum systems. This short review provides an overview over the published scientific results from photon-ion merged-beams experiments at PIPE that were obtained since the start of P04 operations in 2013. The topics covered comprise photoionization of ions of astrophysical relevance, quantitative studies of multi-electron processes upon inner-shell photoexcitation and photoionization of negative and positive atomic ions, precision spectroscopy of photoionization resonances, photoionization and photofragmentation of molecular ions and of endohedral fullerene ions.

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Measurements of absolute photoionisation cross sections of Ca⁺ions

Cited by 68 publications

References 8 publications

Photoionisation of Ca⁺ions in the valence-energy region 20–56 eV: experiment and theory

Photoionisation of Ca⁺ions in the valence-energy region 20–56 eV: experiment and theory

Vacuum-ultraviolet resonant photoabsorption imaging of laser produced plasmas

The photon‐ion merged‐beams experiment PIPE at PETRA III—The first five years

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Measurements of absolute photoionisation cross sections of Ca+ions

Cited by 68 publications

References 8 publications

Photoionisation of Ca+ions in the valence-energy region 20–56 eV: experiment and theory

Photoionisation of Ca+ions in the valence-energy region 20–56 eV: experiment and theory

Vacuum-ultraviolet resonant photoabsorption imaging of laser produced plasmas

The photon‐ion merged‐beams experiment PIPE at PETRA III—The first five years

Contact Info

Product

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Measurements of absolute photoionisation cross sections of Ca⁺ions

Photoionisation of Ca⁺ions in the valence-energy region 20–56 eV: experiment and theory

Photoionisation of Ca⁺ions in the valence-energy region 20–56 eV: experiment and theory