| 1. |
- Guillemin, R., et al.
(författare)
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Selecting core-hole localization or delocalization in CS2 by photofragmentation dynamics
- 2015
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Electronic core levels in molecules are highly localized around one atomic site. However, in single-photon ionization of symmetric molecules, the question of core-hole localization versus delocalization over two equivalent atoms has long been debated as the answer lies at the heart of quantum mechanics. Here, using a joint experimental and theoretical study of core-ionized carbon disulfide (CS2), we demonstrate that it is possible to experimentally select distinct molecular-fragmentation pathways in which the core hole can be considered as either localized on one sulfur atom or delocalized between two indistinguishable sulfur atoms. This feat is accomplished by measuring photoelectron angular distributions within the frame of the molecule, directly probing entanglement or disentanglement of quantum pathways as a function of how the molecule dissociates.
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| 2. |
- Kushawaha, R. K., et al.
(författare)
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Auger resonant-Raman decay after Xe L-edge photoexcitation
- 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
- We have investigated resonant Auger decay of xenon following photoexcitation of each of the three L edges under resonant-Raman conditions, which allowed us to characterize several higher Rydberg transitions. Relative intensities for spectator final states reached after L-1-, L-2-, and L-3-edge excitations are studied in detail. Thanks to state-of-the-art experimental arrangements, our results not only reproduce the previously calculated 3d(-2)5d and nd (n > 5) state cross sections after L-3 excitation, but also allow extracting the 3d(-2)6d spectator state energy position and revealing its resonant behavior, blurred by the insufficient experimental resolution in previous data sets. The 3d(-2)6p and 3d(-2)7p states reached after L-1 excitation as well as the 3d(-2)5d and 3d(-2)6d states reached after L-2 excitation are also investigated and their relative intensities are reported and compared to ab initio Dirac-Hartree-Fock configuration-interaction calculations. We found the signature of electronic-state-lifetime interference effects between several coherently excited intermediate states, due to large lifetime broadening. Electron recapture processes are also identified above all three photoionization thresholds.
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| 3. |
- Puettner, R., et al.
(författare)
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Detailed assignment of normal and resonant Auger spectra of Xe near the L edges
- 2017
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 96:2
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Tidskriftsartikel (refereegranskat)abstract
- We present a comprehensive experimental and theoretical investigation on the LMM, LMN, and LNN normal Auger spectra of xenon, which reveal excellent agreement with theory when core-hole lifetimes of the two-hole final states are taken into account. Generally, the spectra turned out to be highly complex due to a strong overlap of the Auger transitions subsequent to 2s(1/2)(-1), 2p(1/2)(-1), and 2p(3/2)(-1) ionization. This overlap is due to the splitting of the three initial L core holes and the different final M and N core holes being on the same order of magnitude of several hundred eV. The Auger transitions are assigned in detail based on the theoretical results. Most of the MM, MN, and NN final states are described well based on jj coupling. In addition, we present a detailed assignment of the resonant LM45M45 Auger transition subsequent to the 2s -> 6p, 7p and 2p -> 5d, 6d excitations.
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| 4. |
- Goldsztejn, G., et al.
(författare)
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Electronic-state-lifetime interference in the hard-x-ray regime : Argon as a showcase
- 2017
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Ingår i: PHYSICAL REVIEW A. - : AMER PHYSICAL SOC. - 2469-9926. ; 95:1
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Tidskriftsartikel (refereegranskat)abstract
- Electronic-state-lifetime interference is a phenomenon specific for ionization of atoms and molecules in the hard-x-ray regime. Using resonant KL2,3L2,3 Auger decay in argon as a showcase, we present a model that allows extracting the interference terms directly from the cross sections of the final electronic states. The analysis provides fundamental information on the excitation and decay processes such as probabilities of various decay paths and the values of the dipole matrix elements for transitions to the excited states. Our results shed light on the interplay between spectator, shake-down, and shake-up processes in the relaxation of deep core-hole states.
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| 5. |
- Goldsztejn, G., et al.
(författare)
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Ultrafast Dynamics And Electronic State - Lifetime Interferences In Chlorine-Containing Molecules
- 2015
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 635
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Tidskriftsartikel (refereegranskat)abstract
- In order to have access to fine phenomena such as ultrafast nuclear dynamics and electronic state - lifetime interferences (ELI) at high energies (few keV), one has to rely on great experimental resolution. The new experimental HAXPES endstation at the GALAXIES beamline of the French synchrotron SOLEIL provides photons in the 2-12 keV energy range along with a total instrumental resolution below 500 meV. In this work we show experimental evidences of ultrafast nuclear dynamics and ELI on HCl and CH3Cl excited around the Cl 1s resonance. We show also simulations that allow to disentangle the contribution of nuclear dynamics and ELI in our experimental spectra.
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| 6. |
- 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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| 7. |
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| 8. |
- 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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| 9. |
- Ceolin, D., et al.
(författare)
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Auger resonant-Raman study at the Ar K edge as probe of electronic-state-lifetime interferences
- 2015
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 91:2
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Tidskriftsartikel (refereegranskat)abstract
- The resonant-Auger decay in argon following Ar 1s - np excitations was studied under resonant-Raman conditions, i.e., with a total instrumental bandwidth much narrower than the natural linewidth of the absorption features. These state-of-the-art experiments are combined with a radiationless resonant-Raman scattering theory. The main results include identification of the energy position of some high-lying Rydberg states previously masked by insufficient resolution and clear evidence of electronic-state-lifetime interference phenomena.
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| 10. |
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