Infrared photodetachment of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mi>Ce</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:mrow></mml:math>: Threshold spectroscopy and resonance structure

Walter, C. W.; Gibson, N. D.; Janczak, C.M.; Starr, K.A.; Snedden, Ali; Field, Robert L.; Andersson, Pernilla

doi:10.1103/physreva.76.052702

Cited by 40 publications

(20 citation statements)

References 31 publications

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“…It is necessary to mention that some recent studies measured the EA of another lanthanide, Ce, whose yield of the anion is much higher than that of Eu −14 . Although Davis and Thompson suggested a 0.955 ± 0.026 eV EA for Ce based on their LPES experiment21, a subsequent reinterpretation of the LPES data claimed an EA of 0.660 eV22, which is consistent with later experimental results along with the theoretical predictions1923242526. Thus, no significant discrepancy exists in Ce, which is completely different from the present case, Eu.…”

supporting

confidence: 80%

Direct experimental observation of weakly-bound character of the attached electron in europium anion

Cheng

Castleman

2015

Sci Rep

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Direct experimental determination of precise electron affinities (EAs) of lanthanides is a longstanding challenge to experimentalists. Considerable debate exists in previous experiment and theory, hindering the complete understanding about the properties of the atomic anions. Herein, we report the first precise photoelectron imaging spectroscopy of europium (Eu), with the aim of eliminating prior contradictions. The measured EA (0.116 ± 0.013 eV) of Eu is in excellent agreement with recently reported theoretical predictions, providing direct spectroscopic evidence that the additional electron is weakly attached. Additionally, a new experimental strategy is proposed that can significantly increase the yield of the lanthanide anions, opening up the best opportunity to complete the periodic table of the atomic anions. The present findings not only serve to resolve previous discrepancy but also will help in improving the depth and accuracy of our understanding about the fundamental properties of the atomic anions.

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confidence: 80%

Direct experimental observation of weakly-bound character of the attached electron in europium anion

Cheng

Castleman

2015

Sci Rep

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“…This advance has triggered a large number of experimental investigations [2][3][4][5][6][7][8], but some atomic electron affinities and negative-ion fine-structure splittings are still not known to a high precision (sub-meV uncertainty) [9][10][11]. All elements in group III (B, Al, Ga, In, and Tl) form stable negative ions with binding energies of less than 0.5 eV [9], requiring midinfrared light to photodetach at the ground-state threshold.…”

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confidence: 99%

Electron affinity of indium and the fine structure of In−measured using infrared photodetachment threshold spectroscopy

et al. 2010

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Binding energies of the fine-structure levels of the indium negative ion In − are measured using infrared photodetachment threshold spectroscopy. The relative cross section for neutral atom production is measured with a crossed ion-beam-laser-beam apparatus over selected photon energy ranges between 300 and 700 meV. An s-wave threshold is observed due to the opening of the In − (5p 2 3 P 0 ) to In(5p 2 P 1/2 ) ground-state-to-ground-state transition, which determines the electron affinity of In to be 383.92(6) meV. The present result is in good agreement with previous theoretical calculations, but it differs substantially from the previously measured electron affinity and reduces the uncertainty by a factor of 150. s-wave thresholds are also observed for detachment from the excited fine-structure levels of In − , permitting accurate determination of the fine-structure intervals of 76.06(7) meV for J = 0-1 and 170.6(6) meV for J = 0-2, which are in good agreement with the previous measurements and substantially reduce the uncertainties.

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“…In such cases, hydrides of the studied ion could not be separated in the mass analysis and may hence interfere in the results. Reasonably high mass resolution values in photodetachment cross section measurements have been reported by Walter et al 4 In this paper an upgrade of the photodetachment apparatus at the Göteborg University Negative Ion Laser Laboratory (GUNILLA) (Ref. 21) is described.…”

Section: Introductionmentioning

confidence: 87%

“…The first electron affinity determination based on photodetachment cross section measurements was performed on O − in 1955 by Branscomb and Smith 1 using conventional light sources. Soon after, the method of laser photodetachment threshold spectroscopy was developed [2][3][4][5] together with techniques of photodetachment electron spectroscopy, 6 of which the photodetachment microscope is a prominent case. 7 Synchrotron light sources have enabled studies of inner shell photodetachment processes 8 and high power lasers make it possible to investigate negative ions in intense laser fields.…”

Section: Introductionmentioning

confidence: 99%

Ion optical design of a collinear laser-negative ion beam apparatus

Diehl

Wendt

Lindahl

et al. 2011

Review of Scientific Instruments

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An apparatus for photodetachment studies on atomic and molecular negative ions of medium up to heavy mass (M ≃ 500) has been designed and constructed. Laser and ion beams are merged in the apparatus in a collinear geometry and atoms, neutral molecules and negative ions are detected in the forward direction. The ion optical design and the components used to optimize the mass resolution and the transmission through the extended field-free interaction region are described. A 90° sector field magnet with 50 cm bending radius in combination with two slits is used for mass dispersion providing a resolution of M∕ΔM≅800 for molecular ions and M∕ΔM≅400 for atomic ions. The difference in mass resolution for atomic and molecular ions is attributed to different energy distributions of the sputtered ions. With 1 mm slits, transmission from the source through the interaction region to the final ion detector was determined to be about 0.14%.

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Infrared photodetachment ofCe−: Threshold spectroscopy and resonance structure

Cited by 40 publications

References 31 publications

Direct experimental observation of weakly-bound character of the attached electron in europium anion

Direct experimental observation of weakly-bound character of the attached electron in europium anion

Electron affinity of indium and the fine structure of In−measured using infrared photodetachment threshold spectroscopy

Ion optical design of a collinear laser-negative ion beam apparatus

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