Low Energy Bending Modes of Small Carbon Clusters: Laboratory Terahertz Spectroscopy
Zusammenfassung der Projektergebnisse
The project reported here aimed for spectroscopic investigation of gas phase molecules and molecular ions related to astrophysics. As one of six laboratories, the Cologne spectroscopy group participated in the “Associated European Laboratories for High Resolution Spectroscopy” named LEA HiRes. The consortium included groups from France, Belgium and Germany which aimed for developing a regional structure to promote application of high resolution in the field of molecular physics. LEA HiRes was positively evaluated by an international committee of experts, and from 2003 funding was granted by the national funding agencies, FNRS (France), CNRS (Belgium), and DFG (Germany). As contribution to the LEA HiRes objectives, the Cologne group investigated Low Energy Bending Modes of Small Carbon Clusters. The project quickly evolved and in the second period (2006-2009) the objectives were extended to studies on reactive short lived molecules and to molecular ions as well. In collaboration with partners from Belgium and France questions related to atmospheric sciences and to quantum mechanical modeling of intermolecular motions and angular momentum coupling were also addressed. A number of astrophysically important molecules, complexes, and molecular ions have successfully been studied, among them the carbon chain molecules C 3 , HC 3 , DC 3 N, HC 5 N, and HC 7 N, the metal containing molecules TiO, AlO, and TiO 2 , the molecular ions C 2 H 2 +, H 2 D+, D 2 H+, CH 2 D+, CH 5 + and its deuterated isotopologues, the van-der-Waals complex Ne-CO, as well as ground and vibrational excited states of di-methyl ether (DME), H 2 CO, C 2 H 4 , and first spectra of HSSOH and its conformers. Short lived molecules were produced in supersonic jets combined with laser ablation or electrical discharge techniques and studied by means of sub-millimeter and infrared-spectroscopy. For the investigation on cold ions we applied the extremely sensitive method of reaction spectroscopy and reached unprecedented frequency accuracy when locking the signal of an OPO to a frequency comb as reference. The results have been published through more than 30 articles in peer reviewed journals and in two book chapters. The spectral data were introduced as entries to the Cologne Data Base for Molecular spectroscopy (CDMS) which enabled the observations of interstellar C 3 , H 2 D+, vibrationally excited states of DME, and most recently of TiO, and TiO 2 . The project has initiated a number of new collaborations with national and international teams, graduate students and postdocs were introduced to basic and advanced methods in molecular physics and exchange of knowledge among the LEA HiRes group were granted on the basis of regular annual meetings.
Projektbezogene Publikationen (Auswahl)
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Comparison of the cis-bending and C–H stretching vibration on the reaction of C2H2+ with H2 using laser induced reactions. Phys. Chem. Chem. Phys. 7, 1592 (2005)
S. Schlemmer, O. Asvany, T. Giesen
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Experimental Determination of the ν5 cis-Bending Vibrational Frequency and Renner-Teller Structure in Ground State (X2Πu) C2H2+ Using Laser Induced Reactions. Phys. Rev. Lett. 94, 073001 (2005)
O. Asvany, T. Giesen, B. Redlich, S. Schlemmer
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Understanding the LIR Infrared Spectrum of Bare CH5+. SCIENCE 309, 1219 (2005)
O. Asvany, P. Kumar, I. Hegemann, B. Redlich, S. Schlemmer, D. Marx
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The spectrum of ethylene from microwave to submillimetre-wave. Mol. Phys. 104, 273 (2006)
F. Willaert, J. Demaison, L. Margules, H. Mäder, H. Spahn, T. Giesen, A. Fayt
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Overtone spectroscopy of H2D+ and D2H+ using laser induced reactions. J. Chem. Phys. 127, 154317 (2007)
O. Asvany, E. Hugo, F. Müller, J. Tennyson, F. Kühnemann, S. Schiller, S. Schlemmer
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Towards Understanding of H3+ Isotopic and Nuclear Spin Fractionation in Space. In: Molecules in Space & Laboratory, J.L. Lemaire & F. Combes (eds), Paris, 2007
E. Hugo, O. Asvany, J. Harju, S. Schlemmer
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High-Resolution Laboratory Terahertz-Spectroscopy and Applications to Astrophysics. In: Frontiers of Molecular Spectroscopy, Jaan Laane (ed.) (2008)
S. Schlemmer, T. Giesen, F. Lewen, and G. Winnewisser
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Rotational spectra and hyperfine structure of isotopic species of deuterated cyanoacetylene, DC3N. Chem. Phys. 346, 132 (2008)
H. Spahn, H. S. P. Müller, T. F. Giesen, J.-U. Grabow, M. E. Harding, J. Gauss, S. Schlemmer
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Dimethyl Ether: Laboratory Spectra up to 2.1 THz. Torsion-Rotational Spectra within the Vibrational Ground State. Astron. Astrophys. 504, 635 (2009)
C. P. Endres, B. J. Drouin, J. C. Pearson, H. S. P. Müller, F. Lewen, S. Schlemmer, T. F. Giesen
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Rotational Transitions within the 21, 31, 41, and 61 States of Formaldehyde H212C16O. Can. J. Phys. 87, 425 (2009)
L. Margulès, A. Perrin, R. Janeckovà, S. Bailleux, C. P. Endres, T. F. Giesen, S. Schlemmer
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Sub-millimeter wave spectroscopy of the C3H radical: Ro-vibrational transitions from ground to the lowest bending state. J. Mol. Spectrosc. 253, 99 (2009)
M. Caris, T. F. Giesen, C. Duan, H. S. P. Müller, S. Schlemmer, K. M. T. Yamada
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The Rotational Gas-Phase Spectrum of trans- and cis-HSSOH at 100 GHz. J. Mol. Spectrosc. 257, 34 (2009)
M. Koerber, O. Baum, U. Hahn, J. Gauss, T. F. Giesen, S. Schlemmer
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Quantum-induced symmetry breaking explains infrared spectra of CH5+ isotopologues. Nature Chemistry 2, 298 (2010)
S.D. Ivanov, O. Asvany, A. Witt, E. Hugo, G. Mathias, B. Redlich, D. Marx and S. Schlemmer
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Rotational transitions of CH2D+ determined by high-resolution IR spectroscopy. Astron. Astrophys. 516, L3 (2010)
S. Gaertner, J. Krieg, A. Klemann, O. Asvany and S. Schlemmer
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The ν5 antisymmetric stretching mode of linear C7 Revisited in High Resolution. J. Chem. Phys. 132, 224306 (2010)
J. Krieg, V. Lutter, F.-X. Hardy, S. Schlemmer, and T. F. Giesen
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Millimeterwave Spectroscopy of Titanium Dioxide, TiO2. J. Mol. Spectrosc. 268, 173 (2011)
P. Kania, M. Hermanns, S. Brünken, H. S. P. Müller, and T. F. Giesen
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Submillimeter-wave Spectroscopy of the K = 2–1 Subband of the Ne–CO Complex. J. Mol. Spectrosc. 270, 116 (2011)
A. V. Potapov, L. A. Surin, S. Schlemmer, T. F. Giesen
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Frequency comb assisted mid-infrared spectroscopy of cold molecular ions. Review of Scientific Instruments 83, 076102 (2012)
O. Asvany, J. Krieg, and S. Schlemmer
