Hamburg 2009 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 10: Kalte Moleküle 1

MO 10.7: Vortrag

Dienstag, 3. März 2009, 12:15–12:30, VMP 6 HS-G

Gas Phase Vibrational Spectroscopy of Suberate Dianions — •Torsten Wende¹, Daniel J. Goebbert², Risshu Bergmann¹, Gerard Meijer¹, and Knut R. Asmis¹ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — ²Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041

A generally applicable method for forming ion-messenger atom complexes is presented. Mass-selected ions from an electrospray source are trapped and collisionally cooled to sufficiently low temperatures in a buffer gas filled ion trap, such that the formation of the entropically unfavorable complexes occurs via three body collisions. The technique is exploited to measure the first gas phase vibrational spectra of suberate dianions via infrared vibrational predissociation (IRVPD) of the corresponding ion-Kr atom complexes. The IRVPD spectra show that at 63 K the all-trans isomer is the most abundant species, but that dynamically interconverting conformers also contribute to the absorption cross section in the C-H stretching region. Addition of a water molecule leads to a very broad band in the O-H stretching region, which is attributed to strong anharmonic coupling between the O-H stretch modes and intermolecular rocking motion with the H₂O binding to the carboxylate group in a bidentate fashion.