Berlin 2014 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 5: Posters 1: Electronic Spectroscopy, Photochemistry, Femtosecond Spectroscopy
MO 5.1: Poster
Montag, 17. März 2014, 16:30–18:30, Spree-Palais
An improved potential scheme of the system A1Σu+ and 1Πu of Mg2 — •Horst Knöckel, Steffen Rühmann, and Eberhard Tiemann — Quest und Inst. f .Quantenoptik, Leibniz Universität Hannover
We have been investigating the spectra of diatomic alkaline earth metal molecules since few years. The properties of the molecular X1Σg+ ground states in form of precise potential energy curves derived from such investigations are important in view of future applications of the corresponding atoms Mg, Ca and Sr for optical clocks. The ground states of Ca2, Sr2, and recently of Mg2 have been characterized, and cold collision properties like scattering lengths have been given. Experimentally, the vapours of the alkaline earth metal diatomics, here Mg2, are produced in a heat pipe. Methods like conventional absorption spectroscopy employing the high resolution of a Fourier-Transform spectrometer (FTS) or dispersion by the FTS of fluorescence induced by a fixed frequency laser revealed rich spectra. The spectra are more detailed and the transition frequencies are more precise by a factor of about 3 compared to previous studies. We extend the range of known transitions substantially to higher vibrational levels of the upper A1Σu+ state. Moreover, yet unknown perturbations were identified. A model based on potential energy curves will be presented describing the excited A1Σu+ state with good precision, accounting also for the perturbations assuming a coupling by the close lying 1Πu state, for which a potential could also be derived.