| 1. |
- Li, S., et al.
(författare)
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Manifestation of postcollision interaction in Krypton LMN Auger spectra following K-shell photoionization
- 2022
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 106:2
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Tidskriftsartikel (refereegranskat)abstract
- We report on an experimental and theoretical study of postcollision interaction (PCI) effects on L-2 - M4,5N2,3 Auger electrons measured above the Kr K-edge in which L-2 vacancies are primarily generated by KL2 x-ray emission. Such cascade processes, in which a deep inner-shell vacancy decays first by x-ray emission followed by Auger electron emission, is a strong decay mode in heavy atoms. The L-2 - M4,5N2,3 Auger electron peak is observed to become increasingly asymmetric with a shifting peak maximum as the absorbed x-ray energy approaches the K-shell ionization threshold. This is attributed to PCI energy exchanges of the Auger electron with the 1s photoelectron. To model the PCI effects, we have applied a semiclassical approach modified to account for the combined lifetimes of the K and L-2 hole states. In addition, our analysis treats several closely spaced Auger transitions with final ionic states having different terms and angular momenta.
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| 2. |
- Kosugi, S., et al.
(författare)
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Postcollision-interaction effects in multistep Auger transitions following Ar 1s photoionization
- 2022
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 106:3
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Tidskriftsartikel (refereegranskat)abstract
- Postcollision-interaction (PCI) effects involving multistep decay processes following Ar 1s photoionization has been studied by Auger electron spectroscopy. The experiment focused on LMM Auger electrons measured in small photon energy steps across the Ar 1s photoionization threshold. Decay pathways that we studied include (1) the Ar+*2p-1 -> Ar2+3p-2 LMM alpha Auger process due to a single L hole created by KL fluorescence, (2) the Ar2+*2p-2 -> Ar3+*2p-13p-2 LMM1 Auger process following double L shell hole states produced by a KLL Auger processes, and (3) the subsequent Ar3+*2p-13p-2 -> Ar4+3p-4 LMM2 Auger transitions. Particularly pronounced PCI shifts and unusual line shapes compared to the ordinary one-step PCI process were found in the spectra of Auger processes following a KLL Auger first step. The experimental results were compared with calculations based on the semiclassical approach to PCI. Good agreement was found between the calculated and experimental PCI shifts. The result opens possibilities for further studies of the multielectron dynamics between Auger electrons mediated through the photoelectron in these and similar systems.
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| 3. |
- Bomme, C., et al.
(författare)
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Post-collision interaction manifestation in molecular systems probed by photoelectron-molecular ion coincidences
- 2013
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:21, s. 215101-
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Tidskriftsartikel (refereegranskat)abstract
- S1s photoionization in carbonyl sulfide (OCS), followed by multiple Auger decay is investigated both experimentally and theoretically, by means of photoelectron-ion coincidences. A strong influence of post-collision interaction is observed in the energy shift and the distortion of the photoelectron spectra. The magnitude of this effect depends on the total charge of the ionic fragments, i.e., on the number of electrons emitted during the decay of the inner vacancy. A satisfactory agreement is found between experiment and theory, which allows us to estimate the lifetimes of the various two-hole states of the intermediate OCS2+ ion.
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| 4. |
- Guillemin, R., et al.
(författare)
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Photoelectron-Auger-electron angular-momentum transfer in core-ionized Ar : Beyond the standard post-collision-interaction model
- 2019
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 99:6
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Tidskriftsartikel (refereegranskat)abstract
- Electron-ion coincidence experimental data obtained following argon 1s photoionization are reported. Slow photoelectrons were measured in coincidence with Ar+ and Ar2+ ions, and the beta angular distribution parameter was obtained. The measured beta parameter for the Ar2+-photoelectron coincidence measurements shows a significant deviation from the beta = 2 expected value. With the support of a quantum mechanical theory of post-collision interaction (PCI) which goes beyond the standard model, we attribute this deviation to angular-momentum exchange due to the interaction of the photoelectron with the Auger electron, while the role of the residual ion is negligible. The main mechanism of angular-momentum transfer and its effect on the asymmetry parameter beta near the photoionization threshold are considered.
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| 5. |
- Guillemin, R., et al.
(författare)
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Postcollision interaction effects in KLL Auger spectra following argon 1s photoionization
- 2015
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 92:1
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Tidskriftsartikel (refereegranskat)abstract
- Postcollision interaction effects on the Auger decay of a deep core hole are studied both experimentally and theoretically. KL2,L-3(2),(3) decay spectra of the Ar 1s vacancy are measured with high-energy resolution with excess photon energies ranging from 0 to 200 eV above the ionization threshold. Interaction of the Auger electron with the photoelectron and the ion field manifests itself in the Auger spectra as a distortion of the energy distribution of the Auger electron close to threshold. Moreover, recapture of the photoelectron due to energy exchange is dominating in the low-photon-energy range above threshold. The experimental results are compared with calculations based on the semiclassical approach to the postcollision interaction. The energies of the discrete levels and individual recapture cross sections are computed in the Hartree-Fock approximation. Good agreement is found between the calculated and experimental spectra, validating the model used.
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| 6. |
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| 7. |
- Sheinerman, S., et al.
(författare)
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Influence of double Auger decay on low-energy 3d photoelectrons of krypton
- 2012
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 86:2, s. 022515-
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Tidskriftsartikel (refereegranskat)abstract
- Effects of postcollision interaction (PCI) observable in low-energy 3d photoelectron spectra of Kr, which are associated with double Auger decay of the created inner-shell vacancy, are investigated by a combined experimental and theoretical approach. Measurements are based on an efficient multielectron coincidence method. Calculations have been carried out in the framework of a semiclassical approach. Our investigation reveals strong PCI distortion of the photoelectron line shapes, which depends on the kinematics of the process and the characteristics of the double Auger decay.
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