Hyperspherical approach to double-electron excitation of He by fast-ion impact

Journal Article · Sun Dec 01 04:00:00 EST 1991 · Physical Review A. General Physics; (United States)

DOI:https://doi.org/10.1103/PhysRevA.44.7234· OSTI ID:5590353

Moribayashi, K; Hino, K; Matsuzawa, M ^[1]; Kimura, M ^[2]

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1. Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofu-ga-oka Chofu-shi, Tokyo 182 (Japan)
2. Argonne National Laboratory, Argonne, Illinois 60439 (United States) Department of Physics, Rice University, Houston, Texas 77251 (United States)

Double-electron-excitation processes of He atoms by proton, antiproton, and C{sup 6+}-ion impact have been theoretically investigated using the second-order Born approximation and the close-coupling method in the energy regime of MeV/u. The semiclassical impact-parameter method with a straight-line-trajectory approximation is employed to describe the collision processes. Hyperspherical wave functions are adopted to take full account of the strongly correlated motion of two atomic electrons in He. For proton and antiproton impact, it is found that the first-order mechanism dominates for excitation to the (2{ital s}2{ital p}) {sup 1}{ital P{ital o}} excited state, while the second-order processes play a significant role in excitation to the (2{ital s}2{ital s}) {sup 1}{ital S{ital e}}, (2{ital p}2{ital p}){sup 1}{ital S{ital e}}, and (2{ital p}2{ital p}) {sup 1}{ital D{ital e}} excited states at a few MeV/u. It should be noted that the doubly excited (2{ital s}2{ital p}) {sup 1}{ital P{ital o}} state plays an important role as an intermediate state in these second-order processes in addition to the singly excited 1{ital s}2{ital p} {sup 1}{ital P{ital o}} state. It is also found that the difference for the double-electron-excitation processes by proton impact and by antiproton impact is much smaller than that for the double-ionization processes in this energy range. For the C{sup 6+}-ion impact, higher-order mechanisms play more important roles at a few MeV/u. The excitation mechanism is also discussed based on the classification scheme of the correlation quantum numbers, which enables us to obtain a more direct physical insight into the collision mechanism.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• OSTI ID: 5590353
• 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

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEONS
ANTIPARTICLES
ANTIPROTONS
ATOM COLLISIONS
BARYONS
BORN APPROXIMATION
CARBON IONS
CATIONS
CHARGED PARTICLES
COLLISIONS
COMPARATIVE EVALUATIONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVALUATION
EXCITATION
FERMIONS
FLUIDS
GASES
HADRONS
HELIUM
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION COLLISIONS
ION-ATOM COLLISIONS
IONIZATION
IONS
MANY-BODY PROBLEM
MATTER
MEV RANGE
MULTICHARGED IONS
NONMETALS
NUCLEI
NUCLEONS
RARE GASES
TWO-BODY PROBLEM