Hamburg 2009 – scientific programme
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A: Fachverband Atomphysik
A 15: Poster I
A 15.20: Poster
Tuesday, March 3, 2009, 16:30–19:00, VMP 9 Poster
Towards Laser Spectroscopy on Lithium II — •Mariusz Semczuk1,2, Guido Saathoff1, Valentin Batteiger1, Maximilian Herrmann1, Sebastian Knünz1, Hans Schuessler3, Thomas Udem1, and Theodor Hänsch1 — 1Max-Planck-Institut für Quantenoptik, Garching — 2Institute of Experimental Physics, University of Warsaw — 3Dept. of Physics, Texas A&M University, Texas
Simple atomic systems like hydrogen and helium
have been subject to great interest as they allow for sensitive
tests of Quantum Electrodynamics. Helium spectroscopy, in
particular, has been considered as one way of determining an
accurate value of the fine-structure constant. The constant α
can be derived from the fit of a theoretical calculation of the He
23P level fine structure to measured values. While the fine
structure has been measured to high accuracy [1], there is still a
significant discrepancy between two theoretical calculations [2]. In
order to help solve this open problem in bound-state QED, we plan to
measure the 23P fine structure in helium-like Li+. The lithium
ion provides the advantage that it can be trapped and laser-cooled
in an ion trap. Moreover the Li+ fine structure is more sensitive
to higher-order QED terms as these scale with large powers of Z. The
measurement is complicated by hyperfine structure. We thus aim at a
measurement of the complete hyperfine structure multiplet of the
23S1-23P0,1,2 optical transition in 7Li+
to extract both the hyperfine and fine structure simultaneously.
[1] T. Zelevinsky, et al., Phys. Rev. Lett. 95, 203001
(2005).
[2] G.W. F. Drake, Can. J. Phys. 80, 1195 (2002); K. Pachucki,
Phys. Rev. Lett. 97, 013002 (2006)