On trends in total cross sections for electron (positron) scattering on atoms and molecules at intermediate energies

1989 ◽  
Vol 13 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Cz. Szmytkowski
Keyword(s):  
Cross Sections ◽  
Positron Scattering ◽  
Total Cross Sections ◽  
Atoms And Molecules ◽  
Intermediate Energies ◽  
Electron Positron

ABSOLUTE TOTAL CROSS SECTIONS FOR ELECTRON-CH4 SCATTERING AT INTERMEDIATE ENERGIES

2006 ◽  
Author(s):  
M. C. A. LOPES ◽  
M. P. GOMES ◽  
H. COUTO ◽  
W. DE SOUZA MELO ◽  
L. L. DE LIMA
Keyword(s):  
Cross Sections ◽  
Total Cross Sections ◽  
Intermediate Energies

scholarly journals Positron Scattering from Atoms and Molecules

Atoms ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 29 ◽  
Author(s):  
Sultana N. Nahar ◽  
Bobby Antony
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Cross Sections ◽  
Optical Potential ◽  
Inert Gases ◽  
Positron Impact ◽  
Positron Scattering ◽  
Atoms And Molecules ◽  
Section Data ◽  
Theoretical Approaches

A review on the positron scattering from atoms and molecules is presented in this article. The focus on positron scattering studies is on the rise due to their presence in various fields and application of cross section data in such environments. Positron scattering is usually investigated using theoretical approaches that are similar to those for electron scattering, being its anti-particle. However, most experimental or theoretical studies are limited to the investigation of electron and positron scattering from inert gases, single electron systems and simple or symmetric molecules. Optical potential and polarized orbital approaches are the widely used methods for investigating positron scattering from atoms. Close coupling approach has also been used for scattering from atoms, but for lighter targets with low energy projectiles. The theoretical approaches have been quite successful in predicting cross sections and agree reasonably well with experimental measurements. The comparison is generally good for electrons for both elastic and inelastic scatterings cross sections, while spin polarization has been critical due to its sensitive perturbing interaction. Positron scattering cross sections show relatively less features than that of electron scattering. The features of positron impact elastic scattering have been consistent with experiment, while total cross section requires significant improvement. For scattering from molecules, utilization of both spherical complex optical potential and R-matrix methods have proved to be efficient in predicting cross sections in their respective energy ranges. The results obtained shows reasonable comparison with most of the existing data, wherever available. In the present article we illustrate these findings with a list of comprehensive references to data sources, albeit not exhaustive.

scholarly journals Close Coupling Theory of Positron Scattering from Alkali Atoms

1994 ◽  
Vol 47 (6) ◽  
pp. 721 ◽  
Author(s):  
Jim Mitroy ◽  
Kurunathan Ratnavelu
Keyword(s):  
Cross Sections ◽  
Alkali Atom ◽  
Coupling Theory ◽  
Positron Scattering ◽  
Close Coupling ◽  
Total Cross Sections ◽  
Hartree Fock ◽  
Atom Scattering ◽  
Alkali Atoms ◽  
Rearrangement Process

The close coupling equatious for positron-alkali atom scattering are written as a set of coupled momentum-space Lippmann-Schwinger equations. The alkali atom is represented by a frozen-core model based upon the Hartree-Fock approximation. The interaction between the positronium and the residual ion is modified by the inclusion of a core potential. Similarly, a core term is present in the interaction describing the rearrangement process. Close coupling calculations of positron scattering from sodium are performed in a model containing multiple sodium (3s, 3p, 4s, 3d, 4p) and positronium (Is, 2s, 2p) states. Cross sections are reported for an energy range from threshold to 50�eV; the total cross sections are in agreement with experimental data.

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