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Universität zu Köln
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Mathematisch-Naturwissenschaftliche Fakultät
Fachgruppe Physik

I. Physikalisches Institut

THz-spectroscopy

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Many complex molecules are found in molecular clouds and in star forming regions in particular. Understanding their formation is one of the key questions in astrochemistry. Another is how complex can those structures be depending on the actual astrophysical environment, in particular whether being in high and low mass star forming regions. Molecules can be formed mainly via gas phase reactions of ions with neutrals or via surface reaction mechanisms. Presently fairly complex scenarios are considered where some less complex molecules are formed in gas-phase, freeze-out on grains, surface-react, desorb and potentially react further in the gas phase. Observations of particular molecules which are thought to be related in particular reaction schemes can give clues as to what the dominant formation process is.

Many of the complex molecules like ethanol, C2H5OH, can be identified by their rotational lines of the main isotopologue which in many cases are available in Cologne Data Base for Molecular Spectroscopy (CDMS). However, dimethyl ether, CH3OCH3, is an example of a very prominent molecule in space, for which not even this information is available over a sufficient frequency range and thus many astronomical line surveys suffer from the presence of unidentified lines. It is the aim of current projects in the THz spectroscopy group to fix this problem thanks to very high-accuracy measurements in the laboratory.

Contact:Dr. Frank Lewen