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Bray I, Bray AW, Fursa DV, Kadyrov AS. Near-Threshold Cross Sections for Electron and Positron Impact Ionization of Atomic Hydrogen. PHYSICAL REVIEW LETTERS 2018; 121:203401. [PMID: 30500226 DOI: 10.1103/physrevlett.121.203401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Indexed: 06/09/2023]
Abstract
Using classical arguments Wannier [Phys. Rev. 90, 817 (1953)PHRVAO0031-899X10.1103/PhysRev.90.817] proposed an electron-impact ionization cross section for neutral atoms to behave as E^{1.127}, where E is the excess energy above threshold. Using similar arguments Klar [J. Phys. B 14, 4165 (1981)JPAMA40022-370010.1088/0022-3700/14/21/027] obtained E^{2.65} to be the corresponding threshold law for positron impact. Recently, Babij et al. [Phys. Rev. Lett. 120, 113401 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.113401] measured near-threshold positron-impact breakup behavior to be similar to that expected for electrons. Using the convergent close-coupling method for the atomic hydrogen target, we examine cross sections at near-threshold energies for electron and positron impact. Contrary to the experiment, the calculated cross sections are found to behave differently for the two projectiles and consistently with the aforementioned threshold laws, despite the entirely quantum nature of these problems. For electron impact, the threshold behavior holds while the total electron spin asymmetry remains constant, whereas for positron scattering the threshold law holds for breakup while the positronium-formation component of the ionization cross section remains constant.
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Affiliation(s)
- I Bray
- Curtin Institute for Computation and Department of Physics and Astronomy, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia
| | - A W Bray
- Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - D V Fursa
- Curtin Institute for Computation and Department of Physics and Astronomy, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia
| | - A S Kadyrov
- Curtin Institute for Computation and Department of Physics and Astronomy, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia
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2
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Purohit G, Kato D. Dependence of electron impact differential cross sections on the ionic charge to radius ratio for the Al 3+(2p) and Be 2+(1s) ions. J Chem Phys 2018; 148:084307. [PMID: 29495759 DOI: 10.1063/1.5016291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The triple differential cross sections (TDCSs) have been obtained for the electron impact ionization of ionic targets, Al3+(2p) and Be2+(1s), having nearly the same ratio of ionic charge to radius. In the first of this kind of study, the trends of cross sections have been found to match to a greater extent despite ionization taking place from the ionic targets having considerable difference in nuclear charges as well as the ionization taking place from different types of orbitals, p-orbital and s-orbital. The trends of TDCSs have not been found to agree considerably for the neutral Al (3p) and Be (2s) targets.
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Affiliation(s)
- G Purohit
- National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-Cho, Toki, Gifu 509-5292, Japan
| | - D Kato
- National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-Cho, Toki, Gifu 509-5292, Japan
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3
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Zammit MC, Fursa DV, Bray I. Convergent calculations of positron scattering from molecular hydrogen. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1742-6596/635/1/012009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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4
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Pflüger T, Zatsarinny O, Bartschat K, Senftleben A, Ren X, Ullrich J, Dorn A. Electron-impact ionization of neon at low projectile energy: an internormalized experiment and theory for a complex target. PHYSICAL REVIEW LETTERS 2013; 110:153202. [PMID: 25167263 DOI: 10.1103/physrevlett.110.153202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Indexed: 06/03/2023]
Abstract
As a fundamental test for state-of-the-art theoretical approaches, we have studied the single ionization (2p) of neon at a projectile energy of 100 eV. The experimental data were acquired using an advanced reaction microscope that benefits from high efficiency and a large solid-angle acceptance of almost 4π. We put special emphasis on the ability to measure internormalized triple-differential cross sections over a large part of the phase space. The data are compared to predictions from a second-order hybrid distorted-wave plus R-matrix model and a fully nonperturbative B-spline R-matrix (BSR) with pseudostates approach. For a target of this complexity and the low-energy regime, unprecedented agreement between experiment and the BSR model is found. This represents a significant step forward in the investigation of complex targets.
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Affiliation(s)
- Thomas Pflüger
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany and Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Oleg Zatsarinny
- Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA
| | - Klaus Bartschat
- Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA
| | - Arne Senftleben
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Xueguang Ren
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany and Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Joachim Ullrich
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany and Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Alexander Dorn
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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5
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Hubele R, LaForge A, Schulz M, Goullon J, Wang X, Najjari B, Ferreira N, Grieser M, de Jesus VLB, Moshammer R, Schneider K, Voitkiv AB, Fischer D. Polarization and interference effects in ionization of Li by ion impact. PHYSICAL REVIEW LETTERS 2013; 110:133201. [PMID: 23581316 DOI: 10.1103/physrevlett.110.133201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Indexed: 06/02/2023]
Abstract
We present initial-state selective fully differential cross sections for ionization of lithium by 24 MeV O8+ impact. The data for ionization from the 2s and 2p states look qualitatively different from each other and from 1s ionization of He. For ionization from the 2p state, to which in our study the m(L)=-1 substate predominantly contributes, we observe orientational dichroism and for 2s ionization pronounced interference which we trace back to the nodal structure of the initial-state wave function.
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Affiliation(s)
- R Hubele
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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6
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Schneider K, Schulz M, Wang X, Kelkar A, Grieser M, Krantz C, Ullrich J, Moshammer R, Fischer D. Role of projectile coherence in close heavy ion-atom collisions. PHYSICAL REVIEW LETTERS 2013; 110:113201. [PMID: 25166529 DOI: 10.1103/physrevlett.110.113201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Indexed: 06/03/2023]
Abstract
We have measured fully differential cross sections for single ionization and transfer ionization (TI) in 16 MeV O(7+)+He collisions. The impact parameters mostly contributing to single ionization are about an order of magnitude larger than for TI. Therefore, the projectile beam was much more coherent for the latter compared to the former process. The measured data suggest that, as a result, TI is significantly affected by interference effects which are not present in single ionization.
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Affiliation(s)
- K Schneider
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany and Extreme Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, D-64291 Darmstadt, Germany
| | - M Schulz
- Physics Department and LAMOR, Missouri University of Science and Technology, Rolla, Missouri 65409, USA and Institut für Kernphysik, Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt, Germany
| | - X Wang
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany and Shanghai EBIT Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - A Kelkar
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany and Extreme Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, D-64291 Darmstadt, Germany
| | - M Grieser
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - C Krantz
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - J Ullrich
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany and Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany
| | - R Moshammer
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - D Fischer
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
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Fischer D, Globig D, Goullon J, Grieser M, Hubele R, de Jesus VLB, Kelkar A, LaForge A, Lindenblatt H, Misra D, Najjari B, Schneider K, Schulz M, Sell M, Wang X. Ion-lithium collision dynamics studied with a laser-cooled in-ring target. PHYSICAL REVIEW LETTERS 2012; 109:113202. [PMID: 23005625 DOI: 10.1103/physrevlett.109.113202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Indexed: 06/01/2023]
Abstract
We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi,' is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In the inaugural experiment on collisions with 1.5 MeV/amu O(8+)-Li the pure ionization of the valence electron as well as the ionization-excitation of the lithium target was investigated.
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Affiliation(s)
- D Fischer
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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8
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Xu S, Chaluvadi H, Ren X, Pflüger T, Senftleben A, Ning CG, Yan S, Zhang P, Yang J, Ma X, Ullrich J, Madison DH, Dorn A. Low energy (e, 2e) study from the 1t2 orbital of CH4. J Chem Phys 2012; 137:024301. [DOI: 10.1063/1.4732539] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Zatsarinny O, Bartschat K. Nonperturbative treatment of ionization with excitation of helium by electron impact. PHYSICAL REVIEW LETTERS 2011; 107:023203. [PMID: 21797603 DOI: 10.1103/physrevlett.107.023203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Indexed: 05/31/2023]
Abstract
We present cross sections for electron-impact ionization and simultaneous ionization plus excitation of helium by electron impact. The results are obtained from a fully nonperturbative close-coupling formalism using our B-spline R-matrix approach. A large number of pseudostates in the expansion of the wave function represent the coupling to the ionization continuum. We obtain excellent agreement with the directly measured experimental cross section ratios (Bellm et al., Phys. Rev. A 75, 042704 (2007)) for ionization leaving the residual He⁺ ion in either the 1s ground state or the n = 2 (2s + 2p) excited states.
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Affiliation(s)
- Oleg Zatsarinny
- Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA
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10
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Ren X, Senftleben A, Pflüger T, Holzwarth M, Dorn A, Bartschat K, Bray I, Fursa DV, Colgan J, Pindzola MS, Al-Hagan O, Madison DH, Ullrich J. Three-dimensional cross sections for electron impact ionization of atoms and molecules. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1742-6596/212/1/012003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Argenti L, Colle R. Two-Particle Coulomb Green Function Method with Projected Potential: Application to He Double Photoionization. J Phys Chem A 2009; 113:15078-84. [DOI: 10.1021/jp905155w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luca Argenti
- Dipartimento di Chimica Applicata e Scienza dei Materiali (DICASM), Università di Bologna, via del Lazzaretto 15/5, I-40136 Bologna, Italy
| | - Renato Colle
- Dipartimento di Chimica Applicata e Scienza dei Materiali (DICASM), Università di Bologna, via del Lazzaretto 15/5, I-40136 Bologna, Italy
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12
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Laforge AC, Egodapitiya KN, Alexander JS, Hasan A, Ciappina MF, Khakoo MA, Schulz M. Three-body dynamics in single ionization of atomic hydrogen by 75 keV proton impact. PHYSICAL REVIEW LETTERS 2009; 103:053201. [PMID: 19792496 DOI: 10.1103/physrevlett.103.053201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Indexed: 05/28/2023]
Abstract
Doubly differential cross sections for single ionization of atomic hydrogen by 75 keV proton impact have been measured and calculated as a function of the projectile scattering angle and energy loss. This pure three-body collision system represents a fundamental test case for the study of the reaction dynamics in few-body systems. A comparison between theory and experiment reveals that three-body dynamics is important at all scattering angles and that an accurate description of the role of the projectile-target-nucleus interaction remains a major challenge to theory.
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Affiliation(s)
- A C Laforge
- Department of Physics and LAMOR, Missouri University of Science & Technology, Rolla, Missouri, USA
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13
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Kadyrov AS, Bray I, Mukhamedzhanov AM, Stelbovics AT. Coulomb breakup problem. PHYSICAL REVIEW LETTERS 2008; 101:230405. [PMID: 19113531 DOI: 10.1103/physrevlett.101.230405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Indexed: 05/27/2023]
Abstract
We formulate scattering theory in the framework of a surface-integral approach utilizing analytically known asymptotic forms of the three-body wave functions. This formulation is valid for both short-range and Coulombic potentials. The post and prior forms of the breakup amplitude are derived without any reference to renormalization procedures.
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Affiliation(s)
- A S Kadyrov
- ARC Centre for Antimatter-Matter Studies, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia
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14
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Colgan J, Pindzola MS, Robicheaux F, Kaiser C, Murray AJ, Madison DH. Differential cross sections for the ionization of oriented H2 molecules by electron impact. PHYSICAL REVIEW LETTERS 2008; 101:233201. [PMID: 19113547 DOI: 10.1103/physrevlett.101.233201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Indexed: 05/27/2023]
Abstract
A nonperturbative close-coupling technique is used to calculate differential cross sections for the electron-impact ionization of H2 at an energy of 35.4 eV. Our approach allows cross sections for any orientation of the molecule with respect to the incident electron beam to be analyzed. New features in the resulting cross sections are found compared with the case where the molecular orientation is averaged, and also with cross sections for He at equivalent electron kinematics. When averaged over all possible molecular orientations, good agreement is found with recent experimental results.
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Affiliation(s)
- J Colgan
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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15
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Fursa DV, Bray I. Fully relativistic convergent close-coupling method for excitation and ionization processes in electron collisions with atoms and ions. PHYSICAL REVIEW LETTERS 2008; 100:113201. [PMID: 18517783 DOI: 10.1103/physrevlett.100.113201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Indexed: 05/26/2023]
Abstract
We report the development of the fully relativistic convergent close-coupling method based on the solution of the Dirac equation. A complete square-integrable Dirac L-spinor basis is used to obtain a set of target states spanning the target discrete and continuous positive- and negative-energy spectra. The present implementation is for quasi-one-electron atoms whose electronic configuration corresponds to the first column of the periodic table. By way of example, we consider elastic scattering of 7 eV electrons on the ground state of cesium, where the full set of spin asymmetries (A1, A2, Ann) has been measured. Excellent agreement with experiment is found.
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Affiliation(s)
- Dmitry V Fursa
- ARC Centre for Antimatter-Matter Studies, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia
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16
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Dürr M, Dimopoulou C, Najjari B, Dorn A, Ullrich J. Three-dimensional images for electron-impact single ionization of He: complete and comprehensive (e, 2e) benchmark data. PHYSICAL REVIEW LETTERS 2006; 96:243202. [PMID: 16907237 DOI: 10.1103/physrevlett.96.243202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Indexed: 05/11/2023]
Abstract
Comprehensive fully differential cross sections for electron emission into all three spatial dimensions are presented for 1 keV and 102 eV electron-impact single ionization of helium using an advanced reaction microscope. Surprising out-of-plane contributions, traced back to an interference term in a perturbation expansion by comparison with ion-impact data, severely challenge theoretical models that accurately predict coplanar emission. The data represent the ultimate benchmark for recently developed exact theoretical descriptions of the most fundamental three-body quantum problems.
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Affiliation(s)
- M Dürr
- Max-Planck-Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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17
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Bellm S, Lower J, Bartschat K. Electron-impact ionization and excitation of helium to the n=1-4 ionic states. PHYSICAL REVIEW LETTERS 2006; 96:223201. [PMID: 16803305 DOI: 10.1103/physrevlett.96.223201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Indexed: 05/10/2023]
Abstract
We present high-precision (e,2e) measurements and calculations for the e-He four-body Coulomb breakup problem. Cross-section ratios for ionization and excitation of the first three excited states of He+ relative to the ground state have been measured for incident energies between 112 and 319 eV. Comparing the data with predictions from a state-of-the-art hybrid distorted-wave+convergent R matrix with pseudostates (close coupling) approach shows that treating the projectile-target interaction at least to second order is crucial to obtain reasonable agreement between theory and experiment. Nevertheless, our benchmark studies reveal significant theoretical problems for the symmetric energy-sharing cases, thus indicating the need for further improvement.
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Affiliation(s)
- S Bellm
- AMPL, Research School for Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia
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18
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Colgan J, Pindzola MS, Robicheaux F. Lattice calculations of the photoionization of Li. PHYSICAL REVIEW LETTERS 2004; 93:053201. [PMID: 15323692 DOI: 10.1103/physrevlett.93.053201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Indexed: 05/24/2023]
Abstract
Calculations are presented for the double photoionization (with excitation) and triple photoionization of the Li atom. The motion of all three electrons is treated equally by solving the time-dependent Schrödinger equation in nine dimensions. A radial lattice is used to represent three of the nine dimensions, while a coupled channel expansion is used to represent the other six dimensions. Probabilities for photoionization are obtained by t--> infinity projection onto fully antisymmetric spatial and spin functions. Double photoionization cross sections for lithium leaving the ion in the 1s, 2s, and 2p states are presented. Good agreement is found with the measurements of Huang et al. [Phys. Rev. A 59, 3397 (1999)]] for the total double photoionization cross section and with the measurements of Wehlitz et al. [Phys. Rev. Lett. 81, 1813 (1998)]] for the triple photoionization cross section.
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Affiliation(s)
- J Colgan
- Department of Physics, Auburn University, Auburn, AL 36849, USA
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