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

Authors

Andrei Y. Istomin, University of Nebraska-LincolnFollow
Anthony F. Starace, University of Nebraska-LincolnFollow
N. L. Manakov, Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 RussiaFollow
A. V. Meremianin, Voronezh State UniversityFollow
A. S. Kheifets, Australian National UniversityFollow
Igor Bray, Murdoch UniversityFollow

Document Type

Article

Date of this Version

11-10-2005

Comments

Published in Physical Review A 72, 052708 (2005) (11 pages). ©2005 The American Physical Society. Used by permission.
URL: http://link.aps.org/abstract/PRA/v72/e052708
doi:10.1103/PhysRevA.72.052708

Abstract

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 (sigma0), 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 1S0 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, Eexc, 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 Eexc=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.