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Žitnik M, Hrast M, Mihelič A, Bučar K, Turnšek J, Püttner R, Goldsztejn G, Marchenko T, Guillemin R, Journel L, Travnikova O, Ismail I, Piancastelli MN, Simon M, Ceolin D, Kavčič M. Auger Shake-Up Assisted Electron Recapture. PHYSICAL REVIEW LETTERS 2023; 131:203001. [PMID: 38039460 DOI: 10.1103/physrevlett.131.203001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 10/06/2023] [Accepted: 10/16/2023] [Indexed: 12/03/2023]
Abstract
The presence of doubly excited states (DESs) above the core-hole ionization threshold nontrivially modulates the x-ray absorption because the participator Auger decay couples DESs to the underlying low-energy core-hole continuum. We show that coupling also affects the high-energy continuum populated by the spectator Auger decay of DESs. For the K-L_{23}^{2} Auger decay of the 1s^{-1}3p^{-1}4s^{2}^{1}P state in argon, the competing nonresonant path is assigned to the recapture of the 1s photoelectron caused by emission of the fast electron from the shake-up K-L_{23}^{2} decay of the 1s^{-1} ion.
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Affiliation(s)
- M Žitnik
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 31, SI-1000 Ljubljana, Slovenia
| | - M Hrast
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
| | - A Mihelič
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 31, SI-1000 Ljubljana, Slovenia
| | - K Bučar
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 31, SI-1000 Ljubljana, Slovenia
| | - J Turnšek
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 31, SI-1000 Ljubljana, Slovenia
| | - R Püttner
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany
| | - G Goldsztejn
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - T Marchenko
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - R Guillemin
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - L Journel
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - O Travnikova
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - I Ismail
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - M N Piancastelli
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - M Simon
- Sorbonne Université, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France
| | - D Ceolin
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - M Kavčič
- Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 31, SI-1000 Ljubljana, Slovenia
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Abstract
High-resolution K-shell photoionization cross-sections for the C-like atomic nitrogen ion (N+) are reported in the 398 eV (31.15 Å) to 450 eV (27.55 Å) energy (wavelength) range. The results were obtained from absolute ion-yield measurements using the SOLEIL synchrotron radiation facility for spectral bandpasses of 65 meV or 250 meV. In the photon energy region 398–403 eV, 1s⟶2p autoionizing resonance states dominated the cross section spectrum. Analyses of the experimental profiles yielded resonance strengths and Auger widths. In the 415–440 eV photon region 1s⟶(1s2s22p2 4P)np and 1s⟶(1s2s22p2 2P)np resonances forming well-developed Rydberg series up n=7 and n=8 , respectively, were identified in both the single and double ionization spectra. Theoretical photoionization cross-section calculations, performed using the R-matrix plus pseudo-states (RMPS) method and the multiconfiguration Dirac-Fock (MCDF) approach were bench marked against these high-resolution experimental results. Comparison of the state-of-the-art theoretical work with the experimental studies allowed the identification of new resonance features. Resonance strengths, energies and Auger widths (where available) are compared quantitatively with the theoretical values. Contributions from excited metastable states of the N+ ions were carefully considered throughout.
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Abstract
We describe the atomic database of the xstar spectral modeling code, summarizing the systematic upgrades carried out in the past twenty years to enable the modeling of K-lines from chemical elements with atomic number Z≤30 and recent extensions to handle high-density plasmas. Such plasma environments are found, for instance, in the inner region of accretion disks round compact objects (neutron stars and black holes), which emit rich information about the system’s physical properties. Our intention is to offer a reliable modeling tool to take advantage of the outstanding spectral capabilities of the new generation of X-ray space telescopes (e.g., xrism and athena) to be launched in the coming years. Data curatorial aspects are discussed and an updated list of reference sources is compiled to improve the database provenance metadata. Two xstar spin-offs—the ISMabs absorption model and the uaDB database—are also described.
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Finkelstein-Shapiro D, Pullerits T, Hansen T. Two-dimensional Fano lineshapes: Excited-state absorption contributions. J Chem Phys 2018; 148:184201. [PMID: 29764148 DOI: 10.1063/1.5019376] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Fano interferences in nanostructures are influenced by dissipation effects as well as many-body interactions. Two-dimensional coherent spectroscopies have just begun to be applied to these systems where the spectroscopic signatures of a discrete-continuum structure are not known. In this article, we calculate the excited-state absorption contribution for different models of higher lying excited states. We find that the characteristic asymmetry of one-dimensional spectroscopies is recovered from the many-body contributions and that the higher lying excited manifolds have distorted lineshapes that are not anticipated from discrete-level Hamiltonians. We show that the Stimulated Emission cannot have contributions from a flat continuum of states. This work completes the Ground-State Bleach and Stimulated Emission signals that were calculated previously [D. Finkelstein-Shapiro et al., Phys. Rev. B 94, 205137 (2016)]. The model reproduces the observations reported for molecules on surfaces probed by 2DIR.
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Affiliation(s)
| | - Tõnu Pullerits
- Division of Chemical Physics, Lund University, P.O. Box 124, 221 00 Lund, Sweden
| | - Thorsten Hansen
- Department of Chemistry, University of Copenhagen, DK 2100 Copenhagen, Denmark
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Robicheaux F, Loch SD, Pindzola MS, Ballance CP. Contribution of near threshold states to recombination in plasmas. PHYSICAL REVIEW LETTERS 2010; 105:233201. [PMID: 21231457 DOI: 10.1103/physrevlett.105.233201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Indexed: 05/30/2023]
Abstract
Resonance states in atoms or ions at low energies can control the rates of important plasma processes (e.g., dielectronic recombination). We examine the role of states at negative energies just below the ionization threshold of the recombined system and find that they can contribute as much, or more, to recombination as positive energy states. In plasmas, negative energy states can be populated by three body recombination, photorecombination, or continuum lowering. Properly including these negative energy states in a theoretical treatment of plasma processes can change the thermally averaged rate coefficients and, in some cases, removes much of the sensitivity to the energy of a state.
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Affiliation(s)
- F Robicheaux
- Department of Physics, Auburn University, Alabama 36849-5311, USA
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Mihelic A, Zitnik M. Ab initio calculation of photoionization and inelastic photon scattering spectra of He below the N=2 threshold in a dc electric field. PHYSICAL REVIEW LETTERS 2007; 98:243002. [PMID: 17677962 DOI: 10.1103/physrevlett.98.243002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Indexed: 05/16/2023]
Abstract
We study the Stark effect on doubly excited states of the helium atom below N=2. We present the ab initio photoionization and total inelastic photon scattering cross sections calculated with the method of complex scaling for field strengths F <or= 100 kV/cm. The calculations are compared to the measurements of the ion [Phys. Rev. Lett. 90, 133002 (2003)] and vacuum ultraviolet fluorescence yields [Phys. Rev. Lett. 96, 093001 (2006)]. For the case of photoionization and for incident photons with polarization vector P parallel to the electric field F, we confirm the propensity rule proposed by Tong and Lin [Phys. Rev. Lett. 92, 223003 (2004)]. Furthermore, the rule is also shown to apply for F perpendicular to P and for the case of the inelastic scattering in both experimental geometries.
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Affiliation(s)
- Andrej Mihelic
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
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Såthe C, Ström M, Agåker M, Söderström J, Rubensson JE, Richter R, Alagia M, Stranges S, Gorczyca TW, Robicheaux F. Double excitations of helium in weak static electric fields. PHYSICAL REVIEW LETTERS 2006; 96:043002. [PMID: 16486817 DOI: 10.1103/physrevlett.96.043002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Indexed: 05/06/2023]
Abstract
A dramatic electric field dependence has been observed in the fluorescence yield spectrum of the doubly excited states in helium, where a rich phenomenology is encountered below the threshold. Fluorescence yields of certain states can be tuned to zero, while other dipole-forbidden states are significantly enhanced, for fields much weaker than 1 kV/cm. Using an R-matrix multichannel quantum defect theory, spherical-to-parabolic frame transformation method, we are able to reproduce the main features of the observed spectrum, and we discuss the qualitative behavior in terms of weak electric field mixing.
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Affiliation(s)
- Conny Såthe
- Physics Department, Box 530, S-751 21 Uppsala, Sweden
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Gorczyca TW, Rubensson JE, Sathe C, Strom M, Agaker M, Ding D, Stranges S, Richter R, Alagia M. Radiative and relativistic effects in the decay of highly excited states in helium. PHYSICAL REVIEW LETTERS 2000; 85:1202-1205. [PMID: 10991512 DOI: 10.1103/physrevlett.85.1202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2000] [Indexed: 05/23/2023]
Abstract
A recent experimental study [J.-E. Rubensson et al., Phys. Rev. Lett. 83, 947 (1999)] measured a significant fluorescence yield of the He( 2lnl(')) photoexcited resonances, showing major qualitative differences from nonrelativistic predictions. We present a further theoretical study of these states, and perform R-matrix multichannel quantum defect theory calculations to extract fluorescence and ionization cross sections. These theoretical results are in excellent agreement with newer, higher-resolution measurements. Radiative and spin-orbit effects are quantified and shown to play an important role in the overall characterization of highly excited states.
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Affiliation(s)
- TW Gorczyca
- Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5151, USA
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Gorczyca TW, Robicheaux F, Pindzola MS, Badnell NR. Comparisons between perturbative and radiation-damped R-matrix approaches to dielectronic recombination: Application to Ar15+. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1996; 54:2107-2115. [PMID: 9913700 DOI: 10.1103/physreva.54.2107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Gorczyca TW, Robicheaux F, Pindzola MS, Badnell NR. Radiative damping and interference in the resonance structure of the electron-impact excitation cross sections for Ti20+. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:3852-3859. [PMID: 9912695 DOI: 10.1103/physreva.52.3852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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