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MO: Fachverband Molekülphysik
MO 29: Poster: Electronic Spectroscopy
MO 29.2: Poster
Thursday, March 17, 2011, 16:00–18:00, P1
UV Fourier Transform absorption spectroscopy of the A1Σu+ - X1Σg+ system of Mg2 — •Horst Knöckel, Steffen Rühmann, and Eberhard Tiemann — Centre for Quantum Engineering and Space Time Research (QUEST) und Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover
Alkaline earth atoms are currently considered for the development of optical clocks, because they provide narrow optical transitions promising much higher frequency stability and accuracy than the present Cs-based microwave clocks. To reach the ultimate accuracy, e.g. the cold collision properties of the corresponding atoms must be known. Thus precise knowledge of the molecular potential energy curves (PEC) is necessary. While for Ca2 and Sr2 ground and excited states have been characterized, the information for Mg2 is less complete. The Mg2 spectrum lies in the near UV, where tunable lasers are not easily available. Conventional absorption spectroscopy with a UV Fourier transform spectrometer (FTS) was employed. Light from a Deuterium lamp was directed through a Mg/Mg2 heat pipe at 1100K into the FTS. The observed dense spectrum is analyzed with a specific computer program to account for the serious overlap of lines due to the abundances of various isotopologues and wide population distribution. The accuracy of the line frequencies is better by a factor of four compared to previous work and the analysis is improved by directly fitted PECs for both states. For the upper state the range of known levels is extended, and various perturbations are identified, which were not known before.