Journal ArticleDOI
Positronium formation in positron-hydrogen scattering
TLDR
In this paper, the authors used the close-coupling approximation (CCA) to investigate positronium formation into the n=1 and n=2 levels for the positron-hydrogen system.Abstract:
The close-coupling approximation (CCA) has been used to investigate positronium formation into the n=1 and n=2 levels for the positron-hydrogen system. The solution has been obtained by solving integral Lippmann-Schwinger equations in momentum space. The authors have used two basis sets (H(1s,2s,2p)+Ps(1s,2s,2p) and H(1s,2s,2p)+Ps(1s,2s,2p)), which make some allowance for short- and long-range correlation effects in both the incident and positronium channels. These are the first close-coupled results for Ps(n=2) formation. The effect of adding polarization in the positronium channel is found to be significant for Ps formation. A new feature of the present calculations is the use of Gaussian basis functions in the evaluation of the rearrangement matrix elements.read more
Citations
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Journal ArticleDOI
Low-energy positron interactions with atoms and molecules
TL;DR: A review of low-energy positron interactions with atoms and molecules is given in this article, including elastic scattering, electronic and vibrational excitation, ionization, positronium formation and annihilation.
Journal ArticleDOI
Positron collisions with one- and two-electron atoms
TL;DR: In this paper, the current status of coupled-state results for positron scattering by atomic hydrogen and the alkali metals is briefly reviewed and the extension of the coupled state approximation to two-electron targets, i.e., He and alkaline earths, is outlined.
Journal ArticleDOI
Many-body calculations of positron scattering and annihilation from noble-gas atoms
TL;DR: In this paper, the authors applied many-body theory methods to study the interaction of low-energy positrons with noble-gas atoms, and showed that the existence of virtual levels strongly influences the scattering and increases the positron annihilation rate by up to 400 times.
Journal ArticleDOI
Two-center convergent close-coupling approach to positron-hydrogen collisions
Alisher Kadyrov,Igor Bray +1 more
TL;DR: In this article, the question of convergence in two-center close-coupling expansions is addressed via the study of positron-hydrogen scattering, and it is found that the major cross sections do converge if sufficient number of states from a complete basis, centered separately on the hydrogen atom and positronium, are used to expand the total scattering wave function.
Journal ArticleDOI
An 18-state calculation of positron-hydrogen scattering
TL;DR: In this article, the authors reported results for positron scattering by ground-state atomic hydrogen in the energy range 0 to 80 eV. The calculations have been performed in an 18-state Ps(1s, 2s, 3s, 4s) approximation where the pseudostates (denoted by a bar) have been taken from Fon et al. (1981).
References
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The Triplets of Helium
TL;DR: In this paper, the spin effects of the triplets of the helium atom have been investigated, such as the fine structure of triplets and intercombinations between ortho- and para- states.
Journal ArticleDOI
Momentum-space coupled-channels optical method for electron-atom scattering
TL;DR: In this paper, a new method for the solution of the problem of electron scattering by a one-electron atom or ion was proposed, which treated all relevant effects explicitly and treated reaction channels under consideration by the coupled-channels method in momentum space.
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A modification of the close-coupling approximation for e-H scattering allowing for the long-range interactions
R Damburg,E Karule +1 more
TL;DR: The modified close-coupling approximation for e-H scattering was proposed in this article, which exactly accounts for dipole and quadrupole polarization without losing the extremal properties for phase.