The 5p autoionization spectra of Ba atoms excited by electron impact: identification of lines

Hrytsko, V; Kerevičius, Gintaras; Kupliauskiene, A; Borovik, A

doi:10.1088/0953-4075/49/14/145201

Cited by 8 publications

(29 citation statements)

References 30 publications

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“…1. Comparing the spectra shows that low-energy lines 4-17, which reflect the decay of dipole-forbidden states [4], are dominant in the spectrum at 27.5 eV, whereas lines 23-60 associated with dipole-allowed states are most noticeable in the spectrum at 102 eV. However, as will be shown below, the dipole-allowed states possess also the strong excitation maxima at nearthreshold impact energies.…”

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 80%

“…The measuring and the data processing procedure used for obtaining the excitation cross-sections of the autoionizing states were described earlier [7,8] in details. In the present study, the ejected-electron spectra corresponding to the decay of the 5p 5 1 1 2 2 3 3 autoionizing states of Ba atoms were measured by employing an electron spectrometer consisted of a monochromator and an analyzer (both of the 127 ∘ electrostatic type), and an atomic beam source designed for working temperatures up to 700 ∘ C [4]. The incident-and ejected-electron energy resolutions (FWHM) were about 0.2 eV and 0.07 eV, respectively.…”

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 99%

“…The excitation crosssections of autoionizing states were obtained in the form of the energy dependences of the normalized line intensities. In the case of the multichannel decay mode of a particular state [4], its cross-section was obtained as the sum of the normalized intensities of lines corresponding to the all decay channels of this state.…”

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 99%

“…A number of configurations used in the superposition to involve the correlation effects both in the initial and final states was 10199. The detailed description of calculations is presented in [4].…”

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 99%

“…In [3], a strong resonant structure in the excitation cross-sections of the 5p 6 1 1 2 2 states was revealed. Only recently [4], by a combination of the experimental data on the excitation dynamics of ejected-electron spectra and the calculated parameters of the 5p 5 1 1 2 2 3 3 states, all the lines in electron spectra [5,6] and many lines in the photoabsorption spectrum [3] were classified.…”

Section: Introductionmentioning

confidence: 99%

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Electron-Impact Excitation of the 5p55d6s2 Autoionizing States in Ba Atom

et al. 2020

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The excitation cross-sections for the 5p55d6s2 autoionizing states of Ba atoms are studied experimentally and theoretically in an electron-impact energy range from the excitation thresholds of the states up to 600 eV. Experimental data are obtained by determining the intensities of lines in the ejected-electron spectra measured at an observation angle of 54.7∘. The incident-electron and ejected-electron energy resolutions are 0.2 eV and 0.07 eV, respectively. The calculations are performed in the distorted wave approximation by using relativistic radial wave functions obtained in the standard Dirac–Fock–Slater method. For all the states, the experimental cross-sections reach their maxima at low impact energies revealing by that predominantly the spin-exchange character of the excitation of autoionizing states. The structure of the near-threshold maxima indicates the formation of strong negative-ion resonances. At high impact energies, the shape and value of the cross-sections are determined by configuration and state mixing effects.

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Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 80%

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 99%

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 99%

Section: Measuring Procedures and Calculation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electron-Impact Excitation of the 5p55d6s2 Autoionizing States in Ba Atom

et al. 2020

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Photoionization of atomic Ba in the region of the $5p \rightarrow {n}_{1}{{\ell }}_{1}{n}_{2}{{\ell }}_{2}{n}_{3}{{\ell }}_{3}$ excitations

Whitfield

Nook

Wehlitz

2017

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

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We investigate the angular distribution parameters and partial photoionization cross sections of the atomic barium mainline and the , and satellites in the region of the excitations. Our measurements cover the photon energy range from 19.0 eV to 23.0 eV. They are in good qualitative agreement with early experimental investigations of these partial cross sections but were recorded with a significantly improved monochromator resolution detailing the complicated resonance structure in this energy regime. The angular distribution measurements reported here are a significant improvement over the only other angular distribution measurement to date in this resonance region.

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The energy structure and decay channels of the 4p⁶-shell excited states in Sr

Kupliauskiene¹,

Kerevičius²,

Borovik³

et al. 2017

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

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The ejected-electron spectra arising from the decay of the 4p nln l n l 5 ¢ ¢   autoionizing states in Sr atoms have been studied precisely at the incident-electron energies close to excitation and ionization thresholds of the 4p 6 subshell. The excitation behaviors for 58 lines observed between 12 and 21eV ejected-electron kinetic energy have been investigated. Also, the ab initio calculations of excitation energies, autoionization probabilities and electron-impact excitation cross sections of the states 4p nln l n l 5 ¢ ¢   (nl = 4d, 5s, 5p; n l ¢ ¢ = 4d, 5s, 5p; n l   = 5s, 6s, 7s, 8s, 9s, 5p, 6p, 5d, 6d, 7d, 8d, 4f, 5g) have been performed by employing the large-scale configuration-interaction method in the basis of the solutions of Dirac-Fock-Slater equations. The obtained experimental and theoretical data have been used for the accurate identification of the 60 lines in ejected-electron spectra and the 68 lines observed earlier in photoabsorption spectra. The excitation and decay processes for 105 classified states in the 4p 5 5s nl 2 , 4p 5 4d nl 2 and 4p 5 5snln l ¢ ¢ configurations have been considered in detail. In particular, most of the states lying below the ionization threshold of the 4p 6 subshell at 26.92eV possess up to four decay channels with formation of Sr + in 5s 1 2 , 4d 3 2,5 2 and 5p 1 2,3 2 states. Two-step autoionization and two-electron Auger transitions with formation of Sr 2+ in the 4p 6 S 1 0 ground state are the main decay paths for high-lying autoionizing states. The excitation threshold of the 4p 6 subshell in Sr has been established at 20.98±0.05eV.

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The 5p autoionization spectra of Ba atoms excited by electron impact: identification of lines

Cited by 8 publications

References 30 publications

Electron-Impact Excitation of the 5p55d6s2 Autoionizing States in Ba Atom

Electron-Impact Excitation of the 5p55d6s2 Autoionizing States in Ba Atom

Photoionization of atomic Ba in the region of the $5p \rightarrow {n}_{1}{{\ell }}_{1}{n}_{2}{{\ell }}_{2}{n}_{3}{{\ell }}_{3}$ excitations

The energy structure and decay channels of the 4p⁶-shell excited states in Sr

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The 5p autoionization spectra of Ba atoms excited by electron impact: identification of lines

Cited by 8 publications

References 30 publications

Electron-Impact Excitation of the 5p55d6s2 Autoionizing States in Ba Atom

Electron-Impact Excitation of the 5p55d6s2 Autoionizing States in Ba Atom

Photoionization of atomic Ba in the region of the $5p \rightarrow {n}_{1}{{\ell }}_{1}{n}_{2}{{\ell }}_{2}{n}_{3}{{\ell }}_{3}$ excitations

The energy structure and decay channels of the 4p6-shell excited states in Sr

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The energy structure and decay channels of the 4p⁶-shell excited states in Sr