Photoionization of He above the n =2 threshold

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

DOI:https://doi.org/10.1103/PhysRevA.44.7318· OSTI ID:5590408

Sanchez, I; Martriaan, F ^[1]

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1. Departamento de Quimica, Facultad de Ciencias, C-14, Universidad Autonoma de Madrid, 28049 Madrid (Spain)

We report a theoretical study of He(1{ital s}{sup 2})+{ital h}{nu}{r arrow}He{sup +}(1{ital s},2{ital s},2{ital p})+{ital e}{sup {minus}} photoionization processes, for photon energies greater than 65.4 eV. We pay special attention to the energy region 69.0--73.0 eV, where recent synchrotron experiments exhibit clearly resonant structure associated to 3{ital lnl}{prime} doubly excited states of He. Our method is based on a Feshbach partitioning of the total wave function that includes explicitly resonant structure. Total and partial cross sections do not depend on parametrization, although an obvious one can be obtained in a straightforward manner in the vicinity of isolated resonances; this is very useful for the analysis of most of the resonance peaks observed experimentally. An appealing feature of our approach is the use of {ital L}{sup 2}-integrable basis sets to describe the scattering wave functions. Our discretization method provides coupled continuum states with the proper {delta}-function normalization and with the correct asymptotic behavior. With this method, we have calculated partial photoionization cross sections for leaving the ion in the 1{ital s}, 2{ital s}, and 2{ital p} levels, and the results are in good agreement with recently published experimental data. A complete set of parameters describing the first twelve resonances in partial cross sections is also provided.

• OSTI ID: 5590408
• Journal Information: Physical Review A. General Physics; (United States), Vol. 44:11; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HELIUM
PHOTOIONIZATION
EV RANGE
EXCITATION
RESONANCE
SYNCHROTRON RADIATION
THRESHOLD ENERGY
BREMSSTRAHLUNG
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
FLUIDS
GASES
IONIZATION
NONMETALS
RADIATIONS
RARE GASES
664300* - Atomic & Molecular Physics- Collision Phenomena- (1992-)