Approximations for the exchange potential in electron scattering

Riley, Merle E.; Truhlar, Donald G.

doi:10.1063/1.431598

Cited by 460 publications

(143 citation statements)

References 36 publications

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“…To construct this complex potential for each atom, the real part of the potential is represented by the sum of three terms: (i) a static term derived from a Hartree-Fock calculation of the atomic charge distribution, 27 (ii) an exchange term to account for the indistinguishability of the incident and target electrons, 28 and (iii) a polarisation term 29 for the long-range interactions which depend on the target dipole polarisability. 26 The imaginary part, following the procedure of Staszewska et al, 30 then treats inelastic scattering as electron-electron collisions.…”

Section: Numerical Considerationsmentioning

confidence: 99%

Elastic cross sections for electron scattering from GeF4: Predominance of atomic-F in the high-energy collision dynamics

Kato

Suga

Hoshino

et al. 2012

The Journal of Chemical Physics

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We report absolute differential cross sections (DCSs) for elastic electron scattering from GeF4. The incident electron energy range was 3–200 eV, while the scattered electron angular range was typically 15°–150°. In addition, corresponding independent atom model (IAM) calculations, within the screened additivity rule (SCAR) formulation, were also performed. Those results, particularly for electron energies above about 10 eV, were found to be in good quantitative agreement with the present experimental data. Furthermore, we compare our GeF4 elastic DCSs to similar data for scattering from CF4 and SiF4. All these three species possess Td symmetry, and at each specific energy considered above about 50 eV their DCSs are observed to be almost identical. These indistinguishable features suggest that high-energy elastic scattering from these targets is virtually dominated by the atomic-F species of the molecules. Finally, estimates for the measured GeF4 elastic integral cross sections are derived and compared to our IAM-SCAR computations and with independent total cross section values.

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Section: Numerical Considerationsmentioning

confidence: 99%

Elastic cross sections for electron scattering from GeF4: Predominance of atomic-F in the high-energy collision dynamics

Kato

Suga

Hoshino

et al. 2012

The Journal of Chemical Physics

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“…To construct this complex potential for each atom, we followed the procedure proposed by Staszewska et al, 63 where the real part of the potential is represented by the sum of three terms: (i) a static term derived from a Hartree-Fock calculation of the atomic charge density distribution, 64 (ii) an exchange term to account for the indistinguishability of the incident and target electrons, 65 and (iii) a polarization term 66 for the long-range interactions which depends on the target polarizability α. 18 The imaginary part then treats inelastic scattering as electron-electron collisions.…”

Section: Theoretical Outline and Numerical Analysismentioning

confidence: 99%

A comprehensive and comparative study of elastic electron scattering from OCS and CS2 in the energy region from 1.2 to 200 eV

Murai

Ishijima

Mitsumura

et al. 2013

The Journal of Chemical Physics

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We report absolute differential cross sections (DCSs) for elastic electron scattering from OCS (carbonyl sulphide) and CS 2 (carbon disulphide) in the impact energy range of 1.2-200 eV and for scattering angles from 10 • to 150 • . Above 10 eV, the angular distributions are found to agree quite well with our present calculations using two semi-phenomenological theoretical approaches. One employs the independent-atom model with the screening-corrected additivity rule (IAM-SCAR), while the other uses the continuum-multiple-scattering method in conjunction with a parameterfree exchange-polarization approximation. Since OCS is a polar molecule, further dipole-induced rotational excitation cross sections have been calculated in the framework of the first Born approximation and incoherently added to the IAM-SCAR results. In comparison with the calculated DCS for the S atom, atomic-like behavior for the angular distributions in both the OCS and CS 2 scattering systems is observed. Integrated elastic cross sections are obtained by extrapolating the experimental measurements, with the aid of the theoretical calculations, for those scattering angles below 10 • and above 150 • . These values are then compared with the available total cross sections.

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“…͓4͔, and references therein͒. In the present calculations, we use the exchange potential of Furness and McCarthy ͓6,7,25͔, which is derived directly from the formal expression of the nonlocal exchange interaction by using a WKB-like approximation for the wave functions:…”

Section: Optical Potentialmentioning

confidence: 99%

Optical-model potential for electron and positron elastic scattering by atoms

2003

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An optical-model potential for systematic calculations of elastic scattering of electrons and positrons by atoms and positive ions is proposed. The electrostatic interaction is determined from the Dirac-Hartree-Fock self-consistent atomic electron density. In the case of electron projectiles, the exchange interaction is described by means of the local-approximation of Furness and McCarthy. The correlation-polarization potential is obtained by combining the correlation potential derived from the local density approximation with a long-range polarization interaction, which is represented by means of a Buckingham potential with an empirical energydependent cutoff parameter. The absorption potential is obtained from the local-density approximation, using the Born-Ochkur approximation and the Lindhard dielectric function to describe the binary collisions with a free-electron gas. The strength of the absorption potential is adjusted by means of an empirical parameter, which has been determined by fitting available absolute elastic differential cross-section data for noble gases and mercury. The Dirac partial-wave analysis with this optical-model potential provides a realistic description of elastic scattering of electrons and positrons with energies in the range from ϳ100 eV up to ϳ5 keV. At higher energies, correlation-polarization and absorption corrections are small and the usual static-exchange approximation is sufficiently accurate for most practical purposes.

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Approximations for the exchange potential in electron scattering

Cited by 460 publications

References 36 publications

Elastic cross sections for electron scattering from GeF4: Predominance of atomic-F in the high-energy collision dynamics

Elastic cross sections for electron scattering from GeF4: Predominance of atomic-F in the high-energy collision dynamics

A comprehensive and comparative study of elastic electron scattering from OCS and CS2 in the energy region from 1.2 to 200 eV

Optical-model potential for electron and positron elastic scattering by atoms

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