Positron impact ionization of alkali atoms

2020 ◽  
Vol 65 (1-2) ◽  
pp. 5-10
Author(s):  
R.I. Campeanu ◽  
Keyword(s):  
Cross Sections ◽  
Impact Ionization ◽  
Experimental Measurements ◽  
Positron Impact ◽  
Total Cross Sections ◽  
Alkali Atoms ◽  
Positron Collisions

"The models CPE and CPE4, which were successfully used in positron impact ionization studies, are applied to positron impact ionization of Li, Na and K. This work produces total cross sections which are in agreement with the existing theoretical papers and shows the necessity for experimental measurements of these processes. Keywords: Positron collisions; Ionization of Atoms "

Discrepancy in total cross sections of positron-impact ionization of hydrogen

1992 ◽  
Vol 167 (3) ◽  
pp. 277-279 ◽  
Author(s):  
Shih-Wei Hsu ◽  
Tien-Yow Kuo ◽  
Chi-ming J. Chen ◽  
Keh-Ning Huang
Keyword(s):  
Cross Sections ◽  
Impact Ionization ◽  
Positron Impact ◽  
Total Cross Sections

scholarly journals Few Body Effects in the Electron and Positron Impact Ionization of Atoms

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 33
Author(s):  
R.I. Campeanu ◽  
Colm T. Whelan
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Differential Cross ◽  
Impact Ionization ◽  
Inert Gas ◽  
Interference Effects ◽  
Positron Impact ◽  
Competing Interactions ◽  
Energy Sharing

Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions that cannot be separately detected in an experiment with a single projectile. Results will be presented in kinematics where the electron impact ionization appears to be well understood and using the same kinematics positron cross sections will be presented. The kinematics are then varied in order to focus on the role of distortion, post collision interaction (pci), and interference effects.

Differential and total cross sections for antiproton-impact ionization of atomic hydrogen and helium

2009 ◽  
Vol 79 (4) ◽  
Author(s):  
M. McGovern ◽  
D. Assafrão ◽  
J. R. Mohallem ◽  
Colm T. Whelan ◽  
H. R. J. Walters
Keyword(s):  
Cross Sections ◽  
Atomic Hydrogen ◽  
Impact Ionization ◽  
Total Cross Sections

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.

Total cross sections for charge transfer between Alkali Atoms and Halogen Molecules

1969 ◽  
Vol 3 (7) ◽  
pp. 530-531 ◽  
Author(s):  
A.P.M. Baede ◽  
A.M.C. Moutinho ◽  
A.E. de Vries ◽  
J. Los
Keyword(s):  
Charge Transfer ◽  
Cross Sections ◽  
Total Cross Sections ◽  
Alkali Atoms

scholarly journals Positron Impact Ionisation of H and He Atoms: The Continuum Model

1991 ◽  
Vol 44 (3) ◽  
pp. 265 ◽  
Author(s):  
K Ratnavelu
Keyword(s):  
Cross Sections ◽  
Continuum Model ◽  
Optical Potential ◽  
Potential Model ◽  
Experimental Measurements ◽  
Positron Impact ◽  
Optical Potential Model ◽  
Impact Ionisation ◽  
Theoretical Results ◽  
The Continuum

The continuum optical potential model is used to calculate the ionisation cross sections of H and He by positron impact. The present e+-H result is compared with the recent first measurement of e+ -H ionisation cross sections. The e+ -He calculation is also presented, together with the experimental measurements. A comparison with other theoretical results is also given.

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