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978-3-8439-2346-0, Reihe Physik
Jahn Markus Rührig
Excited Diatomic Chromium Molecules
182 Seiten, Dissertation Universität Stuttgart (2015), Softcover, A5
In this thesis I investigate excited diatomic Cr molecules formed by optical pumping of a dense ultracold dipolar quantum gas.
In the first part I discuss the formation of these molecules as a possible limitation for demagnetization cooling of a dipolar gas and experimentally realized a suppression of the losses by a specific choice of the optical pumping detuning. A theoretical model to numerically simulate demagnetization cooling is developed which reproduces the data in good agreement. The simulation helps to gain new insights into further limitations which ultimately prevent demagnetization cooling from reaching quantum degeneracy in Cr.
In the second part the relevant molecular potentials are studied experimentally by photoassociation spectroscopy in a detuning range of up to −20GHz with respect to the atomic resonance. The observed photoassociation resonances are assigned to several series of resonances each belonging to a distinct molecular potential energy curve. The resulting molecular potentials are compared to theoretical calculations of non-rotating relativistic adiabatic potentials and are found to be in good agreement. This constitutes the first experimental study of excited diatomic molecules in a high-spin element of Cr.