88 research outputs found

    PURE ROTATIONAL SPECTRUM OF CN+

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    The pure rotational spectrum of the elusive CN+^+ cation has been observed for the first time using the cryogenic ion trap apparatus Coltrap by applying an action spectroscopy scheme. For the 12^{12}C14^{14}N+^+ species, the three lowest rotational transitions have been observed each of which exhibits hyperfine structure from the presence of the 14^{14}N nucleus. The rare 12^{12}C15^{15}N+^+ isotopolog has been studied up to the J=4‚ąí3J=4-3 transition. The observations conclusively confirm CN+^+ to occupy a 1ő£+^1\Sigma^+ electronic ground state. Given the ubiquity of the CN radical in space, CN+^+ is an appealing candidate for future radio astronomical searches

    FELIX SPECTROSCOPY OF LIKELY ASTRONOMICAL MOLECULAR IONS: HC3O+, C2H3CNH+, and C2H5CNH+

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    Infrared signatures of three molecular ions of relevance to the interstellar medium and planetary atmospheres_x000d_ have been detected at the Free Electron Laser for Infrared eXperiments, FELIX, at Radboud University (Nijmegen, The Netherlands) _x000d_ in combination with the 4K FELion 22-pole ion trap facility. Mid-infrared vibrational modes of protonated tricarbon monoxide, HC3_3O+^+, _x000d_ protonated vinyl cyanide, C2_2H3_3CNH+^+, _x000d_ and protonated ethyl cyanide, C2_2H5_5CNH+^+, were detected using resonant photodissociation of the respective Ne-complexes by monitoring _x000d_ the depletion of their cluster mass signal as a function of wavenumber. The infrared fingerprints compare very favorably_x000d_ with results from high-level quantum-chemical calculations performed at the CCSD(T) level of theory

    THE SOLEIL VIEW ON SULFUR RICH OXIDES: THE _3 MODE OF S2O REVISITED

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    In the course of our recent study of the nu2nu_2 bending mode of S2_2O (Martin-Drumel el al.; see Talk P1190), the S-S stretching mode nu3nu_3 located at 679cm‚ąí1^{-1} and first studied by Lindenmayer textit{et al.} in 1986 (textit{J. Mol. Spectrosc.} textbf{119}, 56) has been re-investigated at the French national synchrotron facility SOLEIL using Fourier-transform far-infrared spectroscopy. In addition to the vibrational fundamental, evidence for at least one more hot band, most likely nu3+nu2‚ąínu2nu_3+nu_2-nu_2, was found. Complementary submillimeter wave measurements of the pure rotational spectrum in the v3=1v_3=1 state were also performed

    ISOTOPE INVARIANT FITTING OF GeO AND GeS AND THE 73Ge QUADRUPOLE MOMENT DERIVED FROM SPECTROSCOPY AND QUANTUM CHEMICAL CALCULATIONS

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    Diatomic germanium oxide, GeO, and germanium sulfide, GeS, have been studied by Fourier transform microwave spectroscopy using laser ablation from a germanium target rod in the presence of H2_2S or O2_2 diluted in neon. Extensive isotopic spectroscopy has been performed; measurements include the ground vibrational state as well as states exceeding v=10v=10 for some species. Ground state rotational spectra of several GeS isotopologs have also been studied around 300\,GHz through a DC discharge of GeCl4_4 and H2_2S in a free-space absorption cell. A global isotope invariant fit has been performed combining all previously published and new high-resolution spectroscopic data. From the analysis of the 73^{73}Ge data combined with highly accurate quantum chemical values for the germanium electric-field gradient, a revised 73^{73}Ge quadrupole moment has been derived

    High-resolution infrared spectroscopy of carbon-sulfur chains: II. C5s and SC5S

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    Unbiased high-resolution infrared survey scans of the ablation products from carbon-sulfur targets in the 2100 to 2150\,cm‚ąí1^{-1} regime reveal two bands previously not observed in the gas phase. On the basis of comparison against laboratory matrix-isolation work\footnote{H. Wang, J. Szczepanski, P. Brucat, and M. Vala 2005, Int. J. Quant. Chem. 102, 795} and new high-level quantum-chemical calculations these bands are attributed to the linear C5_5S and SC5_5S clusters. While polar C5_5S was studied earlier using Fourier-transform microwave techniques,\footnote{Y. Kasai, K. Obi, Y. Ohshima, Y. Hirahara, Y. Endo, K. Kawaguchi, and A. Murakami 1993, ApJ 410, L45},^,\footnote{V. D. Gordon, M. C. McCarthy, A. J. Apponi, and P. Thaddeus 2001, ApJS 134, 311} the present work marks the first gas-phase spectroscopic detection of SC5_5S

    DOPPLER AND SUB-DOPPLER MILLIMETER AND SUB-MILLIMETER WAVE SPECTROSCOPY OF KEY ASTRONOMICAL MOLECULES: HNC AND CS

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    In the course of ongoing efforts to determine accurate pure rotational transition frequencies for the astronomical community, the millimeter- and submillimeter-wave spectra of HNC and selected isotopic species have been investigated using a radio-frequency discharge of (isotopically enriched) methyl cyanide. Besides the ground vibrational state, vibrational satellites from the first excited bending mode were targeted. In part, rotational transitions were observed employing the Lamb-Dip technique to obtain sub-Doppler resolution. The Lamb-dip technique has also been applied to other short-lived molecules such as carbon monosulfide, CS

    Synergy of multifrequency studies from observations of NGC6334I

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    We combine multifrequency observations from the millimeter to near infrared wavelengths that demonstrate the spatial distributions of H2, CO, and NH3 emission, which are all manifestations of various shocks driven by outflows of deeply embedded sources in NGC6334I. In addition to the well-known northeast-southwest outflow we detect at least one more outflow in the region by combining observations from APEX, ATCA, SMA, Spitzer and VLT/ISAAC. Potential driving sources will be discussed. NGC6334I exhibits several signs of active star formation and will be a major target for future observatories such as Herschel and ALMA.Comment: 6 pages, 6 figures, appeared in the proceedings of the workshop 'The Universe Under The Microscope - Astrophysics At High Angular Resolution', see http://www.iop.org/EJ/toc/1742-6596/131/

    MICROWAVE DETECTION OF PROTONATED SO2_2 IN TWO ISOMERIC FORMS

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    Author Institution: Harvard-Smithsonian Center for Astrophysics, 60 Garden St.; Cambridge, MA 02138, and School of Engineering \& Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138; Max-Planck-Institut fur Radioastronomie, Auf dem Hugel 69, 53121 Bonn, GermanyBy means of Fabry-Perot FT microwave spectroscopy, the rotational spectrum of protonated sulfur dioxide in two distinct isomeric forms, a \textit{cis} and a \textit{trans} geometry, is reported. Searches for both isomers were based on theoretical structures obtained at the CCSD(T)/cc-pwCVQZ level of theory corrected for zero-point vibrational effects at the CCSD(T)/cc-pV(T+dd)Z level. At a similarly high level of theory, the \textit{cis} isomer is calculated to be the global minimum on the potential energy surface, but the \textit{trans} isomer is predicted to lie only a few kcal/mol higher in energy. The identification of \textit{cis} HOSO+^+ has been confirmed by detection of rotational lines of DOSO+^+ and HO34^{34}SO+^+ at precisely the expected frequency shifts. Because sulfur dioxide is a well known interstellar and extragalactic species, and because it possesses a large proton affinity, HOSO+^+ is a excellent candidate for radioastronomical detection
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