Berlin 2014 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 7: Fathoming Stellar Evolution (Part 2)
MS 7.2: Hauptvortrag
Mittwoch, 19. März 2014, 17:00–17:30, DO24 1.205
High-resolution spectroscopy of (deuterated) molecular ions — •Oskar Asvany, Sandra Brünken, Sabrina Gärtner, Pavol Jusko, Lars Kluge, Alexander Stoffels, and Stephan Schlemmer — I. Physikalisches Institut, Universität zu Köln, Köln, Germany
One phenomenon in the initial phases of star formation is the deuteration of molecules and ions observed in many different environments. Since several decades there is a vivid interplay between astronomical detections and laboratory measurements in this field, recent examples being the tentative observation of CH2D+ towards Orion IRc2 and the firm detection of para-H2D+ towards I16293 in Ophiuchus using the GREAT receiver on the SOFIA airplane.
This talk concentrates on the laboratory methods to obtain rotational and rovibrational spectra of mass-selected molecular ions of astronomical interest. High-resolution is achieved by cooling and trapping a few thousand ions in a multipolar trap, while using narrow-band IR or mm-wave sources for their excitation. This excitation is detected by action spectroscopy, laser induced reactions (LIR) being the main workhorse in our laboratory.
Recently, the arsenal of action spectroscopy methods has been enriched by the newly developed method of Laser Induced Inhibition of Cluster Growth (LIICG), in which attachment of He atoms to ionic species below 10 K is hindered by resonant excitation. Advantages of LIICG are operation at 4 K, its apparent applicability to any ion, and response to any sort of excitation (rotational/vibrational/electronic), as will be shown on selected examples (CD2H+, H3+, CO+).