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The confined variational method is used to study the elastic scattering of the positron from the ground-state helium with the scattering energy in the range from 0.05 eV to 11.02 eV. Describing the correlation effect with explicitly correlated Gaussians, we obtain accurate phase shifts, S-wave scattering length, elastic scattering cross sections, and annihilation parameters for different incident momenta. Specifically, by a least-squares fit of the data to the effective-range theory, we determine the room temperature annihilation parameter Zeff = 3.955, which is in perfect agreement with the measured result of 3.94 ± 0.02 [J. Phys. B 8, 1734 (1975)].
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Electron-positronium scattering and Ps - photodetachment
Abstract We investigate the fundamental three-body Coulomb process of elastic electron-positronium (e--Ps) scattering below the Ps(n = 2) threshold. Using the complex Kohn variational method and trial wave functions that contain highly correlated Hylleraas-type terms, we accurately compute1,3S-,1,3P-, and1,3D-wave phase shifts, which may be considered as benchmark results. We explicitly investigate the effect of the mixed symmetry term in the short-range part of the1,3D-wave trial wave function on the phase shifts and resonances. Using the complex Kohn phase shifts we compute, for e−-Ps scattering, the elastic differential, elastic integrated, momentum-transfer, and ortho-para conversion cross sections and determine the importance of the complex Kohn D-wave phase shifts on these cross sections. In addition, using the short-range part of the1S-wave trial wave function for the bound state of the purely leptonic ion of Ps−, and the complex Kohn1P trial wave function for the continuum state, we determine the Ps−photodetachment cross section in the length, velocity, and acceleration forms.
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- Award ID(s):
- 2207886
- PAR ID:
- 10576944
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Journal of Physics B: Atomic, Molecular and Optical Physics
- ISSN:
- 0953-4075
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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