Some comments on positron–atom scattering at intermediate energy

A brief survey of available theoretical techniques is given for positron–atom scattering. The distinction between methods involving a finite number of target states and those with an infinite number of target states is emphasized. The situation regarding total cross sections is summarized, and a new, non-perturbative, eikonal-type approximation, based on the work of Wallace, is introduced.

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Close Coupling Theory of Positron Scattering from Alkali Atoms

Australian Journal of Physics ◽

10.1071/ph940721 ◽

1994 ◽

Vol 47 (6) ◽

pp. 721 ◽

Cited By ~ 22

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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Metastable hydrogen atom scattering by crossed molecular beams: Total cross-sections for H(2s)–Kr, O2 and Cl2 at thermal energies

Chemical Physics Letters ◽

10.1016/s0009-2614(98)00463-1 ◽

1998 ◽

Vol 290 (1-3) ◽

pp. 17-23 ◽

Cited By ~ 4

Author(s):

Brunetto G. Brunetti ◽

Pietro Candori ◽

Jaime De Andres ◽

Stefano Falcinelli ◽

Marta Stramaccia ◽

...

Keyword(s):

Hydrogen Atom ◽

Cross Sections ◽

Molecular Beams ◽

Total Cross Sections ◽

Atom Scattering ◽

Crossed Molecular Beams

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GENETIC PROGRAMMING APPROACH FOR ELECTRON-ALKALI-METAL ATOM COLLISIONS

International Journal of Modern Physics B ◽

10.1142/s0217979206035825 ◽

2006 ◽

Vol 20 (32) ◽

pp. 5463-5471 ◽

Cited By ~ 4

Author(s):

SALAH YASEEN EL-BAKRY ◽

AMR RADI

Keyword(s):

Experimental Data ◽

Genetic Programming ◽

Cross Sections ◽

Alkali Metal Atom ◽

Intermediate Energy ◽

Target Atom ◽

Programming Approach ◽

Dipole Polarizability ◽

Total Cross Sections ◽

Alkali Atoms

New technique is presented for modeling the total cross sections of electron scattering by Na, K, Rb and Cs atoms in the low and intermediate energy regions. The calculations have been performed in the framework of genetic programming (GP) technique. The GP has been running based on the experimental data of the total collisional cross sections to produce the total cross sections for each target atom. The incident energy and atomic number as well as the static dipole polarizability have been used as input variables to find the functions that describe the total collisional cross sections of the scattering of electrons by alkali atoms. The experimental, calculated and predicted total collisional cross sections are compared. The discovered functions show a good match to the experimental data.

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