Düsseldorf 2007 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 10: Poster I - Precisions Spectroscopy

A 10.1: Poster

Dienstag, 20. März 2007, 16:30–18:30, Poster B

Low–lying level structure of atomic nobelium and lawrencium: A challenge for ab–initio theory — •S. Fritzsche¹, C. Z. Dong², G. Gaigalas³, and M. Sewtz⁴ — ¹Universität Kassel, D–34132 Kassel, Germany — ²Northwest Normal University, Lanzhou 730070, China — ³Vilnius Research Institute of Theoretical Physics and Astronomy, — ⁴LMU München, D-85748 Garching, Germany

Studies on the transuranium elements have attracted a lot of interest during the last two decades, both by experiment and theory. Beside the challenge of identifying new elements, these investigations aim for a better understanding of the electronic structure in strong fields as well as for insights into the chemical binding in Nature.

In this contribution, we report on relativistic multiconfiguration Dirac–Fock calculations for the low–lying excitation spectrum of atomic nobelium (Z=102) and lawrencium (Z=103). For these elements, there are strong effects of relativity, electron correlations, and bound–state relaxation (for atomic transitions) which must be treated coherently within the same framework [1]. Based on detailed computations for the low–lying resonances, and including the analysis of the absorption rates, two fermium resonances at 25099.8 cm⁻¹ and 25111.8 cm⁻¹ could be identified recently [2] and have raised the hope that such resonances will be observed also for other heavy elements [3] in the near future using resonance ionization spectroscopy (RIS).

[1] S. Fritzsche, J. Electr. Spec. Rel. Phenon. 114–116, 1155 (2001).

[2] M. Sewtz et al., Phys. Rev. Lett. 90, 163002 (2003).

[3] S. Fritzsche, Eur. Phys. J. D33, 15 (2005).