Formation of positronium in e sup + +H sup minus collisions

Journal Article · Sat Nov 30 23:00:00 EST 1991 · Physical Review A. General Physics; (United States)

DOI:https://doi.org/10.1103/PhysRevA.44.7335· OSTI ID:5394794

Straton, J C ^[1]; Drachman, R J ^[2]

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1. Department of Physics, Cardwell Hall, Kansas State University, Manhattan, Kansas 66506 (United States)
2. Laboratory for Astronomy and Solar Physics, Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

Cross sections for positronium formation by capture from the negative hydrogen ion are given. Orthogonalization corrections to the Coulomb (first-order) Born approximation (CBA) differential and total cross sections are calculated using approximate H{sup {minus}} wave functions of both Loewdin (Phys. Rev. 90, 123 (1953)) and Chandrasekhar (Astrophys. J. 100, 176 (1944)). The present calculation of the CBA cross sections using the post interaction for Loewdin's wave function (LCBAPS) disagrees with the calculation of Choudhury, Mukherjee, and Sural (CMS) (Phys. Rev. A 33, 2358 (1986)), whereas our results using the prior interaction agree. Thus, where CMS found an order of magnitude post-prior discrepancy in the differential cross sections except at forward angles, and a markedly different shape to the minima, the present post and prior results differ by 1--10 % at 100 eV, and the minima have the same shape and occur within one degree of each other. Chandrasekhar's open-shell'' wave function, which is superior to Loewdin's in bound-state problems since it gives a negative binding energy, gives post and prior cross sections that are almost indistinguishable at this energy and are 1/2 to 2/3 as large as the LCBA. Various methods of orthogonalizing the unbound projectile to the possible bound states are considered. It is found that treating the atomic nuclei as if they were isotopic spin projections (Straton and Girardeau, Phys. Rev. A 40, 2991 (1989)) of a single type of nucleon'' gives cross sections that are an improvement over the CBA.

• OSTI ID: 5394794
• Journal Information: Physical Review A. General Physics; (United States), Journal Name: Physical Review A. General Physics; (United States) Vol. 44:11; ISSN 1050-2947; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

664500* -- Special Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
BINDING ENERGY
BORN APPROXIMATION
BOUND STATE
CAPTURE
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELECTRON CAPTURE
ENERGY
FUNCTIONS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
ION COLLISIONS
IONS
ISOSPIN
NEBULAE
PARTICLE PROPERTIES
PLANETARY NEBULAE
POSITRON COLLISIONS
POSITRON-ION COLLISIONS
POSITRONIUM
SOLAR ACTIVITY
SOLAR FLARES
WAVE FUNCTIONS