17O12C17O and18O12C17O spectroscopy in the 1.6 μm region

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FEMTO-FANTASIO: A VERSATILE EXPERIMENTAL SET-UP TO INVESTIGATE MOLECULAR COMPLEXES

Author Institution: Service de Chimie quantique et Photophysique CP160/09, Faculte des Sciences, Universite Libre de Bruxelles (U.L.B.), Av. Roosevelt, 50, B-1050, Bruxelles, BelgiumSeveral improvements have been made on the apparatus developed in Brussels for the study of jet-cooled molecules, named \hbox{FANTASIO nderline{\textbf{105}}(5-7), 815 (2007).} nderline{\textbf{463}}, 345 (2008).} nderline{\textbf{113}}, 2359 (2009).}}, for "Fourier trANsform, Tunable, diode and quadrupole mAss spectrometers interfaced to a Supersonic expansIOn". The upgraded setup, called Femto-FANTASIO, is presented.\\ These improvements include: a doubling of the pumping efficiency, by adding another turbomolecular pump Leybold MAG-W3200 CT; an increase in sensitivity in the 1.5 $\mu$m range thanks to a new CRDS system, consisting in new cavity mirrors, leading to a ring down time of 125 $\mu$s and a new detector, decreasing the noise level; a new injection system to probe samples liquid at STP conditions; a temperature controlled nozzle/slit; and as an alternative probe technique, an absorption source, tunable from 3000 to 9000 cm$^{-1}$, coupling an optical parametric oscillator (OPO), pumped by a Ti:Sa femtosecond laser, to a high resolution continuous scan Fourier transform interferometer.\\ Femto FANTASIO will be used to investigate molecular complexes. First results and achievements of this new setup are presented

High sensitivity (femto-FT-CEAS) spectra of carbonyl sulphide between 6200 and 8200cm−1, and new energy pattern in the global rovibrational analysis of 16O12C32S

We have recorded Fourier transform spectra of OCS between 6170 and 6680 cm-1, and between 7700 and 8160 cm-1 using a femto/OPO laser absorption source and cavity enhanced spectroscopy. Equivalent absorption path lengths varying between 7 and 13 km were obtained depending on the specific spectral region. In the lower and higher energy ranges, 7 and 12 new bands were observed, respectively, while improved results were gained on those previously reported in the literature. Some of these data brought significant, new information on the rovibrational energy pattern in OCS that triggered an update of the latest published global polyad model (Rbaihi et al. J Mol Spectrosc 1998;191:32). The new fit includes for the first time all overtone data since published in the literature, covering the range 6200 – 13950 cm-1, as well as all known lower energy ones. All data selected for the global analysis of carbonyl sulfide 16O12C32S are provided as supplementary information. The previous polyad model was extended to include the inter-polyad anharmonic k1113 and Coriolis C11222 interactions, leading to simultaneously deal with sets of nine interacting polyad matrices at a time, each polyad defined by N = 2v1+v2+4v3 (with 1 to 3 the conventional nomal modes in OCS). We have obtained a statistical agreement with all experimental data with an estimated standard deviation better than unity ( = 0.7568). The fit produced 141 molecular parameters, of which 4 concern the new inter-polyad resonances. They have been used to calculate effective rovibrational parameters for all sub-states up to more than 12000 cm-1, listed in a Depository. A list of line parameters, covering the measured spectral ranges and including line intensities determined using previously recorded Fourier transform spectra of the two strongest bands observed in the present work, was generated in HITRAN format. It is also provided as supplementary information

Femto-FT-CEAS investigation of rare acetylene isotopologues (H12C13CD, D12C13CH and D12C13CD)

The infrared spectrum of a sample containing C-13 mono-substituted isotopologues of acetylene, (HCCH)-C-12-C-13, (HCCD)-C-12-C-13, (DCCH)-C-12-C-13 and (DCCD)-C-12-C-13 has been recorded in the 6130-6800cm(- 1) region using a femto-Fourier transform-cavity enhanced absorption spectroscopy (femto-FT-CEAS) apparatus. Three bands for both (HCCD)-C-12-C-13 and (DCCH)-C-12-C-13 were observed and analysed, namely 2(1) - GS and associated hot bands from (4) and (5). The assignment of the 2(1) overtone already reported in the literature [J.L. Hardwick, Z.T. Martin, M.J. Pilkenton, E.N. Wolf, J. Mol. Spectrosc. 243, 10 (2007)] was considerably extended to higher J values. For the (DCCD)-C-12-C-13 isotopologue, four bands were analysed, (1) + (2) + (3) - GS and associated hot bands from (4) and (5) and 2(1) + (4) + (5) - G

THE FANTASIO SET-UP (I): DESCRIPTION AND EXTENSION TOWARDS FEMTO-FANTASIO

M. Herman, K. Didriche, D. Hurtmans, B. Kizil, P. Macko, A. Rizopoulos and P. Van Poucke, Mol. Phys., \underline{105Author Institution: Service de Chimie quantique et Photophysique CP160/09, Faculte des Sciences, Universite Libre de; Bruxelles (U.L.B.), Av. Roosevelt, 50, B-1050, Bruxelles, Belgium; Laboratoire de; Spectrometrie Physique, Laboratoire de Spectrométrie Physique, Universite Joseph Fourier de; Grenoble, B.P. 87, 38402 Saint-Martin-d'Heres Cedex, FranceWe have built the FANTASIO set-up (for "Fourier trANsform, Tunable diode and quadrupole mAss spectrometers interfaced to a Supersonic expansIOn") to investigate jet-cooled molecules and dimers, 843 (2007). }. The set-up will be described. New developments are on the way, to be illustrated by preliminary results. These include the doubling of the vacuum pumping system efficiency. They will also allow for a Femto OPO system to be used as a broadband, cavity enhanced absorption source to be interfaced to the supersonic expansion and to the high resolution FTIR instrument of FANTASIO

INTERIOR POINT METHODS FOR COMBINATORIAL OPTIMIZATION

Research on using interior point algorithms to solve combinatorial optimization and integer programming problems is surveyed. This paper discusses branch and cut methods for integer programming problems, a potential reduction method based on transforming an integer programming problem to an equivalent nonconvex quadratic programming problem, interior point methods for solving network flow problems, and methods for solving multicommodity flow problems, including an interior point column generation algorithm