Low-energy positron-argon collisions by using parameter-free positron correlation polarization potentials

Journal Article · Wed Feb 28 23:00:00 EST 1990 · Physical Review, A (General Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevA.41.2437· OSTI ID:6996563

Jain, A ^[1]

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1. Department of Physics, Box 981, Florida A M University, Tallahassee, Florida 32307 (US)

We report differential, integral, and momentum-transfer cross sections and the scattering length ({ital A}{sub 0}) for positron ({ital e}{sup +})-argon scattering at low energies below the positronium formation threshold. An optical-potential approach is employed in which the repulsive Coulombic interaction is calculated exactly at the Hartree-Fock level and the attractive polarization and correlation effects are included approximately via a parameter-free positron correlation polarization (PCP) potential recently proposed by us. The PCP model is based on the correlation energy {var epsilon}{sub corr} of one positron in a homogeneous electron gas; in the outside region, the {var epsilon}{sub corr} is joined smoothly with the correct asymptotic form of the polarization interaction ({minus}{alpha}{sub 0}/2r{sup 4}, where {alpha}{sub 0} is the target polarizability) where they cross each other for the first time. The total optical potential of the {ital e}{sup +}-argon system is treated exactly in a partial-wave analysis to extract the scattering parameters. It is found that the PCP potential gives much better qualitative results, particularly for the differential cross sections and the scattering length, than the corresponding results obtained from an electron polarization potential used as such for the positron case. We also discuss the critical'' points (representing the minima in the differential scattering) in the low-energy {ital e}{sup +}-Ar scattering. The present results involve no fitting procedure.

• DOE Contract Number: FC05-85ER25000
• OSTI ID: 6996563
• Journal Information: Physical Review, A (General Physics); (USA), Journal Name: Physical Review, A (General Physics); (USA) Vol. 41:5; ISSN PLRAA; ISSN 0556-2791
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DIMENSIONS
ELASTIC SCATTERING
ELEMENTS
ENERGY RANGE
EV RANGE
EV RANGE 01-10
FLUIDS
GASES
LENGTH
NONMETALS
POLARIZATION
POSITRON COLLISIONS
POSITRON-ATOM COLLISIONS
POTENTIALS
RARE GASES
SCATTERING
SCATTERING LENGTHS
SENSITIVITY ANALYSIS