Determination of complex scattering amplitudes in low-energy elastic electron-sodium scattering

McClelland, Jabez J.; Lorentz, Steven R.; Scholten, R. E.; Kelley, Michael H.; Celotta, Robert

doi:10.1103/physreva.46.6079

Cited by 26 publications

(7 citation statements)

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“…In two recent publications, Blum and Lohmann [1] and Lohmann et al [2] discussed a tunable entanglement in elastic electron collisions with atomic hydrogen or light alkali atoms, where explicitly spin-dependent interactions may be neglected and the process is completely described by two independent parameters, namely the absolute angle-differential cross section (DCS) and a spin-correlation parameter P , which (except for the opposite sign) is the exchange asymmetry A ex that was measured by the Bielefeld [3,4] and NIST [5] groups many years ago. Due to the available experimental data, Lohmann et al [2] presented results for P = −A ex from various close-coupling calculations for atomic hydrogen and sodium, but only for selected energies as a function of the scattering angle, and for lithium, but only at selected angles as a function of energy.…”

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confidence: 99%

Spin entanglement in elastic electron scattering from lithium atoms

Bartschat

Santos

2017

Phys. Rev. A

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In two recent papers (Phys. Rev. Lett. 116 (2016) 033201; Phys. Rev. A 94 (2016) 032331), the possibility of continuously varying the degree of entanglement between an elastically scattered electron and the valence electron of an alkali target was discussed. In order to estimate how well such a scheme may work in practice, we present results for elastic electron scattering from lithium in the energy regime of 1−5 eV and the full range of scattering angles 0 • − 180 • . The most promising regime for Bell-correlations in this particular collision system are energies between about 1.5 eV and 3.0 eV, in an angular range around 110 • ± 10 • . In addition to the relative exchange asymmetry parameter, we present the differential cross section that is important when estimating the count rate and hence the feasibility of experiments using this system.

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confidence: 99%

Spin entanglement in elastic electron scattering from lithium atoms

Bartschat

Santos

2017

Phys. Rev. A

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“…To analyze experiments involving preparation of the initial state and/or analysis of the final state we require three density operators: for the initial state, for the state that results from mapping (13), and for detection or analysis of the final state. The simplest case is one in which there is no initial-state preparation, e.g.…”

Section: Density Operators For Experimentsmentioning

confidence: 99%

“…ase dlfFerence between the ML =+1 and -1 amplitudes in each spin channel, while the triplet-singlet phase angles 5+, (8) In a series of papers [8,9,11,13,15], McClelland and co-workers have measUred spin-dependent cross sections and OA parameters for elastic (3s -+3s) and superelastic (3p~3s ) scattering of beams of spin-polarized electrons from beams of state-selected Na atoms in order to resolve scattering in the singlet and the triplet spin channels. Qf particular interest here are experiments that use optical pumping to spin polarize the initial atoms along the z ' axis of the natural frame, normal to the scattering plane.…”

Section: Singlet and Triplet Alignment Anglesmentioning

confidence: 99%

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Low-energy electron collisions with sodium: Scattering of spin-polarized electrons

et al. 1995

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The electron-sodium system is a prototype of nonrelativistic electron scattering from a quasi-oneelectron atomic target and is tractable both experimentally and theoretically. Recently, this system has been studied in a series of sophisticated measurements that together approach complete experiments for elastic (3s~3s) and inelastic (3s~3@)scattering. We apply here the theory of orientation and alignment (OA) in atomic collisions to this system using scattering matrices from coupled channel R-matrix calculations described in the first paper in this series [W. K. Trail et al. , Phys. Rev. A 49, 3620 (1994)]. To facilitate the extension of OA theory to other transitions and systems and to clarify its relationship to canonical scattering theory, we present a reformulation in terms of the state spaces identified by a particular scattering event. Following the application of this formulation to paradigmatic OA experiments, we compare our results to those from existing measurements and other theoretical calculations. To contextualize these experiments and aid in identifying promising regions for future measurements, we also present a comprehensive three-dimensional overview of the calculated differential OA parameters for energies from threshold to 8.6 eV.PACS number (s): 34.80.8m, 34.80. Dp, 34.80.Nz 'Present address: trends and structures that distinguish and characterize this system. The cross sections considered in Ref. [1] do not fully describe the physics of e-Na collisions. Until the past two decades, most scattering experiments measured "conventional" diff'erential (DCSs) and/or integrated cross sections (ICSs) that implicitly involve averages over initial and sums over Anal spin and orbital magnetic substates. These necessary averages obscure much of the dynamical information contained in the scattering amplitudes. More recently, however, experiments [2 -17] have become feasible that use a variety of techniques to prepare the target atoms in an initial nonequilibrium distribution of magnetic and/or spin substates or to detect the magnetic and/or spin substates of the results of a scattering event. Such experiments have dramatically increased our understanding of atomic collisions and provide data that test theories at a more fundamental level than was heretofore possible [18 -32].In the present paper, therefore, we extend this inquiry to a class of experiments that uses initial-state preparation and/or final-state analysis to look more deeply into the physics of low-energy e-Na scattering. Rather than DOS's, these experiments measure less familiar quantities snch as exchange asymmetries and triplet-singlet phase angles; the importance of these "orientation and alignment (OA) parameters" rests in their often subtle physical interpretation and in their relationship to the scattering amplitudes for the transitions in questionmatters we shall address in Sec. II. As in Ref.[1], we focus here on scattering from the ground state, considering the two transitions for which data are available: elastic scattering and the...

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“…Shortly thereafter similar studies on Ba (see, e.g., Register et al 1978Register et al , 1983 were initiated in our laboratory. Measurements have been reported subsequently on Na (Herman and Hertel 1982, McClelland et al 1992, Sang et al 1994, Hall et al 1996, Ba (Zetner et al 1990, Li and Zetner 1994a, Ca Teubner 1995, Teubner et al 1996), Li (Karagonov et al 1996, Rb (Hall et al 1996), Cr (Hanne et al 1993) and Yb (Li and Zetner 1994b). In these studies the superelastic scattering signal corresponding to the electron-impact de-excitation of the laser-prepared state to the ground state was measured as a function of the laser geometry and polarization (with respect to the collision frame).…”

Section: Introductionmentioning

confidence: 99%

Elastic electron scattering by laser-excited¹³⁸Ba( ... 6s6p¹P₁) atoms

Trajmar

Kanik

Khakoo

et al. 1999

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

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Abstract.The results of a joint experimental and theoretical study concerning elastic electron scattering by laser-excited 138 Ba(. . . 6s6p 1 P 1 ) atoms are described. These studies demonstrate several important aspects of elastic electron collisions with coherently excited atoms, and are the first such studies. From the measurements, collision and coherence parameters, as well as cross sections associated with an atomic ensemble prepared with an arbitrary in-plane laser geometry and linear polarization (with respect to the collision frame), or equivalently with any magnetic sublevel superposition, have been obtained at 20 eV impact energy and at 10 • , 15 • and 20 • scattering angles. The convergent close-coupling (CCC) method was used within the non-relativistic LS-coupling framework to calculate the magnetic sublevel scattering amplitudes. From these amplitudes all the parameters and cross sections at 20 eV impact energy were extracted in the full angular range in 1 • steps. The experimental and theoretical results were found to be in good agreement, indicating that the CCC method can be reliably applied to elastic scattering by 138 Ba(. . . 6s6p 1 P 1 ) atoms, and possibly to other heavy elements when spin-orbit coupling effects are negligible. Small but significant asymmetry was observed in the cross sections for scattering to the left and to the right. It was also found that elastic electron scattering by the initially isotropic atomic ensemble resulted in the creation of significant alignment. As a byproduct of the present studies, elastic scattering cross sections for metastable 138 Ba atoms were also obtained.

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Determination of complex scattering amplitudes in low-energy elastic electron-sodium scattering

Cited by 26 publications

References 24 publications

Spin entanglement in elastic electron scattering from lithium atoms

Spin entanglement in elastic electron scattering from lithium atoms

Low-energy electron collisions with sodium: Scattering of spin-polarized electrons

Elastic electron scattering by laser-excited¹³⁸Ba( ... 6s6p¹P₁) atoms

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Determination of complex scattering amplitudes in low-energy elastic electron-sodium scattering

Cited by 26 publications

References 24 publications

Spin entanglement in elastic electron scattering from lithium atoms

Spin entanglement in elastic electron scattering from lithium atoms

Low-energy electron collisions with sodium: Scattering of spin-polarized electrons

Elastic electron scattering by laser-excited138Ba( ... 6s6p1P1) atoms

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Elastic electron scattering by laser-excited¹³⁸Ba( ... 6s6p¹P₁) atoms