INVESTIGADORES
GASANEO Gustavo
congresos y reuniones científicas
Título:
C3-like double continuum and double bound wave-functions for two-electron systems
Autor/es:
L. U. ANCARANI AND G. GASANEO
Lugar:
Königstein, Alemania
Reunión:
Simposio; International Symposium on (e,2e), Double Photoionization and Related Topics; 2007
Resumen:
In the theoretical study of the double ionization of helium, whether by electron ((e,3e) experiments) [1] or photon ((γ,2e) experiments) [2] impact, approximate wave-functions are used in cross sections calculations: different choices, however, generally lead to different results [1-5]. The balanced description of the initial and final two-electron states seems to play a key role in reproducing experimental data. The purpose of this contribution is to define balanced double-bound ground an excited states with respect to the widely used double-continuum three-body Coulomb (C3) wave function [6] (also called 3C or BBK model). A first step towards this aim was achieved in [7] where the doubly bound analog of the C3 wave function was derived, for S-states of two-electron systems, by a double analytic continuation of the double continuum C3 wave-function. The result is given by the product of two hydrogenic wave functions (with two quantum numbers) and a Coulomb distortion function which depends on a non-linear parameter. However, this bound wave function contains no radial and only a limited amount of angular correlation. To go further, we pursue the investigation by proposing two basis sets of C3-like functions. The first one which contains non-linear parameters, is composed of the bound analog functions themselves. In the second one, we associate a third quantum number to the electron-electron distortion factor, making the basis parameter-free. These basis sets can be used, in a Configuration Interaction approach, to construct highly-correlated two-electron wave functions for bound S states which are of the same family as that describing the double continuum C3. Results for the ground and first excited states of several helium-like atoms will be presented at the conference.   Acknowledgments: This work has been supported by PICTR 2003/0437 of the ANPCYT, PGI 24/F038 of the Universidad Nacional del Sur and PIP5595 of the CONICET.   References   [1] J. Berakdar, A. Lahmam-Bennani and C. Dal Cappello Phys.Rep. 374, 91 (2003) [2] J. S. Briggs and V. Schmidt, J. Phys. B 33, R1 (2000) [3] L.U. Ancarani, T.Montagnese and C. Dal Cappello, Phys. Rev.A 70, 12711 (2004) [4] S. Jones, J. H. Macek and D. H. Madison, Phys. Rev. A 70, 12712 (2004) [5] L.U. Ancarani and C. Dal Cappello, in J. of Electron Spectroscopy and Related      Phenomena, in press, (2007) [6] C. R. Garibotti and J. E. Miraglia, Phys. Rev. A 21, 572 (1980); M. Brauner, J. Briggs        and H. Klar, J. Phys. B 22, 2265 (1989) [7] L.U. Ancarani and G. Gasaneo, Phys. Rev. A 75, 032706 (2007)