Parametrizations and dynamical analysis of angle-integrated cross sections for double photoionization including nondipole effects

Journal Article · Tue Nov 15 04:00:00 EST 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.72.0· OSTI ID:20786511

Istomin, Andrei Y; Starace, Anthony F; Manakov, N L; Meremianin, A V; Kheifets, A S; Bray, Igor ^[1]

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1. Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States)

Similarly to differential cross sections for one-electron photoionization, the doubly differential cross section for double photoionization (DPI) may be conveniently described by four parameters: the singly differential (with respect to energy sharing) cross section ({sigma}{sub 0}), the dipole asymmetry parameter ({beta}), and two nondipole asymmetry parameters ({gamma} and {delta}). Here we derive two model-independent representations for these parameters for DPI from a {sup 1}S{sub 0} atomic bound state: (i) in terms of one-dimensional integrals of the polarization-invariant DPI amplitudes and (ii) in terms of the exact two-electron reduced matrix elements. For DPI of He at excess energies, E{sub exc}, of 100 eV, 450 eV, and 1 keV, we present numerical results for the asymmetry parameters within the framework of the convergent close-coupling theory and compare them with results of lowest-order (in the interelectron interaction) perturbation theory (LOPT). The results for E{sub exc}=1 keV exhibit a nondipole asymmetry that is large enough to be easily measured experimentally. We find excellent agreement between our LOPT results and other theoretical predictions and experimental data for total cross sections and ratios of double to single ionization cross sections for K-shell DPI from several multielectron atoms.

• OSTI ID: 20786511
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
ASYMMETRY
ATOMS
BOUND STATE
COMPARATIVE EVALUATIONS
COUPLING
DIFFERENTIAL CROSS SECTIONS
DIPOLES
ELECTRONS
EV RANGE
K SHELL
KEV RANGE
MATRIX ELEMENTS
ONE-DIMENSIONAL CALCULATIONS
PERTURBATION THEORY
PHOTOIONIZATION
PHOTON-ATOM COLLISIONS
POLARIZATION
TOTAL CROSS SECTIONS