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Research in Atomic Physics

PICTURE OF THE GROUP

RESEARCH ACTIVITY AND RESEARCH TOPICS:

Physics of the inner shells of atoms is studied using x-ray and synchrotron radiation. Recent work involves multiple photoexcitation, i.e. the process in which a photon can change quantum states of two or more electrons in the atom. The experiments provide information on collective motion in the atomic system. Absorption spectroscopy is the main experimental technique, recently complemented by high resolution fluorescence spectroscopy.

MAIN RESULTS:

Lower limits for KL photoexcitation in 3d transition elements: - The experiment disproved a number of earlier results in multiple photoexcitation
L-subshell photoexcitation in Xe: - First study of the angular momentum effect on multiple photoexcitation. Observation of indirectly excited 4d shape resonance.
KL photoabsorption in argon: - Splitting of KL resonances explained by configuration interaction.
Multiple excitation in isoelectronic ion series: - Studies of the gradual change of the process in consecutive ions following noble gas atoms. To avoid structural effects in x-ray absorption, samples in special chemical states (solutions, gels, glasses, vapors) are introduced. A new "white line rule" has been established.
EXAFS spectra of various compounds: - In collaboration with several chemical labs at the J. Stefan Institute and the National Institute of Chemistry structures of amorphous materials (high Tc superconductors, electrocromic thin film coatings, ceramic precursors, bonded magnet ceramics) inaccessible to x-ray diffraction was determined.

CURRENT INTERNATIONAL COLABORATION AT:

Current international colaboration at: Hasylab at DESY, Hamburg, Germany with Dr. Ronald Frahm, Wolfgang Drube, Larc Troeger on the projects:: Investigations of systematic properties of multielectron photoexcitation (1994-1995)
Absorption spectra of Rb vapor (1995)
LURE, Paris-Orsay, France with Dr. Alain Fontain, Dr. Philippe Parent and Dr. Francoise Villain: Multiple photoexcitations by x-ray absorption and fluorescence (1994-1995)

MOST IMPORTANT ARTICLES

I. Arcon, A. Kodre, M. Hribar, The Influence of Secondary Extinction on Bragg Reflectivity Extended Fine Structure (BREFS), 2nd European Conference on Progress in X-ray Synchrotron Radiation Research, Rome 2.-6. October 1989, edit.: A. Balerna, E. Bernieri, and S. Mobilio, Conf. Proceedings V 25, Bologna, (1990), p.419-422.
Kodre, M. Hribar, I. Arcon, D. Glavic-Cindro, M. Stuhec, and R. Frahm, W. Drube, Search for Multiple K+L Photoionization in Solid Transition Elements by X-ray Absorption Spectroscopy, Phys. Rev. A 45 (1992) 4682-4687.
M. Stuhec, A. Kodre, M. Hribar, I. Arcon, D. Glavic-Cindro, W. Drube, Configuration Interaction in Argon KL Resonances, Phys. Rev, A 49, (1994) 3104-5.
A. Kodre, I. Arcon, M. Hribar, M. Stuhec, F. Villain, P. Parent, Double Photoexcitation [2(s,p)4(p,d)] in the Xe-Isoelectronic Series Cs+, Ba2+, La3+, J. de Physique (Paris) - Colloque C9, Vol 4 (1994) 397-400.
I. Arcon, M. Bele, M. Hribar, A. Kodre, S. Pejovnik, M. Stuhec, W. Drube, EXAFS Analysis of Intermediate Phases in the Synthesis of the YBa2Cu3O7-x high-Tc Superconductor From Xerogel, J. de Physique (Paris) - Colloque C9, Vol 4 (1994) 105-108.
I. Arcon, A. Kodre, M. Stuhec, D. Glavic-Cindro, W. Drube, Multielectron Excitations in the L-Subshell Photoabsorption of xenon, Phys. Rev. A 51 (1995).

Last update April 3, 1996; dgc