Hyperspherical approach to double-electron excitation of He by fast-ion impact
- Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofu-ga-oka Chofu-shi, Tokyo 182 (Japan)
- 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), Vol. 44:11; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON IONS
ION-ATOM COLLISIONS
HELIUM
HYDROGEN IONS 1 PLUS
ANTIPROTONS
BORN APPROXIMATION
COMPARATIVE EVALUATIONS
EXCITATION
IONIZATION
MEV RANGE
MULTICHARGED IONS
TWO-BODY PROBLEM
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEONS
ANTIPARTICLES
ATOM COLLISIONS
BARYONS
CATIONS
CHARGED PARTICLES
COLLISIONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVALUATION
FERMIONS
FLUIDS
GASES
HADRONS
HYDROGEN IONS
ION COLLISIONS
IONS
MANY-BODY PROBLEM
MATTER
NONMETALS
NUCLEI
NUCLEONS
RARE GASES
664300* - Atomic & Molecular Physics- Collision Phenomena- (1992-)