We have studied methyl formate, one of the so-called ‘astronomical weeds’, in the 214-265 GHz band. We have experimentally gathered a set of intensity calibrated, complete, and temperature resolved spectra from across the astronomically significant temperature range of 248-406 K. Using our previously reported method of analysisJ. McMillan, S. Fortman, C. Neese, F. DeLucia, ApJ. 795, 56 (2014) the point by point method, we are capable of generating the complete spectrum at an arbitrary temperature. Thousands of lines, of nontrivial intensity, which were previously not included in the available astrophysical catalogs have been found. The sensitivity of the point by point analysis is such that we are able to identify lines which would not have manifest in a single scan across the band. The consequence has been to reveal not only a number of new methyl formate lines, but also trace amounts of contaminants. We show how the intensities from the contaminants can be removed with indiscernible impact on the signal from methyl formate. To do this we use the point by point results from our previous studies of these contaminants. The efficacy of this process serves as strong proof of concept for usage of our point by point results on the problem of the ‘weeds’. The success of this approach for dealing with the weeds has also previously been reported.S. Fortman, J. McMillan, C. Neese, S. Randall, and A. Remijan, J. Mol. Spectrosc. 280, 11 (2012).html:<hr /><h3>Footnotes: J. McMillan, S. Fortman, C. Neese, F. DeLucia, ApJ. 795, 56 (2014), S. Fortman, J. McMillan, C. Neese, S. Randall, and A. Remijan, J. Mol. Spectrosc. 280, 11 (2012).

Recently we studied the rotational spectrum of hydroxyacetonitrile (HOCH₂CN, HAN) in order to provide a firm basis for its possible detection in the interstellar mediumMargulès L., Motiyenko R.A., Guillemin J.-C. 68th ISMS, 2013, TI12. Different plausible pathways of the formation of HAN in the interstellar conditions were proposed;Danger G. et al. Phys. Chem. Chem. Phys. 2014, 16, 3360.owever, up to now, the searches for this molecule were unsuccessful. To continue the study of nitriles that represent an astrophysical interest we present in this talk the analysis of the rotational spectrum of 4-hydroxy-2-butynenitrile (HOCH₂CC-CN, HBN), the next molecule in the series of hydroxymethyl nitriles. Using the Lille spectrometer the spectrum of HBN was measured in the frequency range 50 - 500 GHz. From the spectroscopic point of view HBN molecule is rather similar to HAN, because of -OH group tunnelling in gauche conformation. As it was previously observed for HAN, due to this large amplitude motion, the splittings in the rotational spectra of HBN are easily resolved making the spectral analysis more difficult. Additional difficulties arise from the near symmetric top character of HBN (κ = −0.996), and very dense spectrum because of relatively small values of rotational constants and a number of low-lying excited vibrational states. The analysis carried out in the frame of reduced axis system approach of PickettPickett H.M. J. Chem. Phys. 1972, 56, 1715.llows to fit within experimental accuracy all the rotational transitions in the ground vibrational state. Thus, the results of the present study provide a reliable catalog of frequency predictions for HBN.
The support of the Action sur Projets de l’INSU PCMI, and ANR-13-BS05-0008-02 IMOLABS is gratefully acknowledged

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Margulès L., Motiyenko R.A., Guillemin J.-C. 68th ISMS, 2013, TI12.. Danger G. et al. Phys. Chem. Chem. Phys. 2014, 16, 3360.h Pickett H.M. J. Chem. Phys. 1972, 56, 1715.a

Various astronomical objects show distinctive series of IR emission bands indicated as unidentified infrared emission bands. These features are nowadays mainly attributed to the IR fluorescence of Polycyclic Aromatic Hydrocarbons (PAHs) even though an unambiguous identification of which PAHs are involved has not been possible yet. We present here a high-resolution IR absorption study of a number of jet-cooled polycyclic aromatic hydrocarbons in the 3.3 μm region obtained by IR-UV ion depletion techniques. The experimental spectra display many more bands than expected, and lead to the conclusion that the appearance of the spectrum is dominated by fourth-order vibrational coupling terms. This has far-reaching consequences since up till now the assignment of infrared emission features observed in different types of space objects in this wavelength region -and the conclusions drawn from these assignments on the evolution of interstellar gas- has relied heavily on harmonic quantum chemical calculations. We also observe that the presence of bay-hydrogen sites in a PAH leads to a shift of the overall spectrum to the high-energy side and to a broadening of the 3 μm band. This observation provides an appealing explanation for previous speculations that the emission of 3 μm band consists of two components. Moreover, it paves for using this structure to derive the composition of different objects.

Sagittarius (Sgr for short) B2 is the most massive and luminous star-forming region in our Galaxy, located close to the Galactic Center. We have carried out a molecular line survey with the IRAM 30 m telescope toward its two major sites of star-formation, Sgr B2(M) and (N).A. Belloche et al., A&A 559 (2013) Art. No. A47.oward the latter source, which is particularly rich in Complex Organic Molecules (COMs), we detected three molecules for the first time in space, aminoacetonitrile, ethyl formate, and n-propyl cyanide. We have recently obtained ALMA data of Sgr B2(N) between  ∼ 84 and  ∼ 111 GHz within Cycle 0 and one additional setup up to 114.4 GHz within Cycle 1. At angular resolutions of 1.8" and 1.4", respectively, the two main hot cores, the prolific Sgr B2(N-LMH) (or Sgr B2(N)-SMA1) and the likely less evolved Sgr B2(N)-SMA2 are well separated, and line confusion is reduced greatly for the latter. As a consequence, we have been able to identify the first branched alkyl molecule in space, iso-propyl cyanide, toward Sgr B2(N)-SMA2.A. Belloche et al., Science 345 (2014) 1584.ur ongoing analyses include investigations of cyanides and isocyanides, alkanols and thioalkanols, and deuterated molecules among others. We will present some of our results.

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A. Belloche et al., A&A 559 (2013) Art. No. A47.T A. Belloche et al., Science 345 (2014) 1584.O

Ethyl cyanide (CH₃CH₂CN) is one of the most abundant complex organic molecules in the interstellar medium firstly detected in OMC-1 and Sgr B2 in 1977D. R. Johnson, et al., Astrophys. J. 1977, 218, L370 The vibrationally excited states are enough populated under ISM conditions and could be detectedA. Belloche, et al., A&A 2013, 559, A47A.M. Daly, et al., Astrophys. J. 2013, 768, 81 Apart from the deuterated ones, all mono-substituted isotopologues of ethyl cyanide (¹³CK. Demyk, et al. A&A 2007 466, 255 nd ¹⁵NMargulès, et al. A&A 2009, 493, 565 have been detected in the ISM. The detection of isotopologues in the ISM is important: it can give information about the formation process of complex organic molecules, and it is essential to clean the ISM spectra from the lines of known molecules in order to detect new ones. The ¹²C/¹³C ratio found in SgrB2: 20-30 suggests that the doubly ¹³C could be present in the spectral line survey recently obtained with ALMA (EMoCA)Belloche et al. 2014, Science, 345, 1584 but no spectroscopic studies exist up to now. We measured and analyzed the spectra of the ¹³C-doubly-substitued species up to 1 THz with the Lille solid-state based spectrometer. The spectroscopic results and and the detection of the doubly ¹³C species in SgrB2 will be presented.
This work was supported by the CNES and the Action sur Projets de l'INSU, PCMI. This work was also done under ANR-13-BS05-0008-02 IMOLABS. Support by the Deutsche Forschungsgemeinschaft via SFB 956, project B3 is acknowledged

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D. R. Johnson, et al., Astrophys. J. 1977, 218, L370. A. Belloche, et al., A&A 2013, 559, A47, A.M. Daly, et al., Astrophys. J. 2013, 768, 81. K. Demyk, et al. A&A 2007 466, 255 a Margulès, et al. A&A 2009, 493, 565) Belloche et al. 2014, Science, 345, 1584,

The aldimines are important to understand amino acids formation process as they appear in reaction scheme of Strecker-type synthesis. Following the detection in the ISM of methanimine (CH₂NH) in 1973Godfrey, P. D.; et al. Astrophys. Lett. 13, (1973) 119nd the more recent one of ethanimine (CH₃CHNH)Loomis, R. A.; et al. ApJ. Lett. 765, (2013) L9 we decided to investigate the next molecule in the series: propanimine (CH₃CH₂CHNH). For this molecule no spectroscopic information was available up to now. We measured the rotational spectrum of propanimine in the frequency range up to 500 GHz. Since the spectroscopic studies of ethanimine were limited to 130 GHzLovas, F. J.; et al. J. Chem. Phys. 72, (1980) 4964 we also extended the measurements up to 300 GHz. The spectra of both E- and Z- isomers are analyzed for the two molecules. Usually aldimines, which are unstable molecules, are obtained by discharge or pyrolysis methods, here pure sample were obtained by synthesis process.
For ethanimine, the methyl top internal rotation should be taken into account, therefore the analysis is performed using new version of RAM36 codeIlyushin, V.V. et al;J. Mol. Spectrosc. 259, (2010) 26hich includes the treatment of the nuclear quadrupole hyperfine structure.
The spectroscopic results and their searches in Orion will be presented.
This work was supported by the CNES and the Action sur Projets de l'INSU, PCMI. This work was also done under ANR-13-BS05-0008-02 IMOLABS

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Godfrey, P. D.; et al. Astrophys. Lett. 13, (1973) 119a Loomis, R. A.; et al. ApJ. Lett. 765, (2013) L9, Lovas, F. J.; et al. J. Chem. Phys. 72, (1980) 4964, Ilyushin, V.V. et al;J. Mol. Spectrosc. 259, (2010) 26w

The λ 5797.1 DIB is unique with its sharp central feature.T.H. Kerr, R.E. Hibbins, S.J. Fossey, J.R. Miles, P.J. Sarre, ApJ 495, 941 (1998)e simulated the spectrum based on three premises: (1) Its carrier molecule is polar as concluded from the anomalous spectrum toward the star Herschel 36.T. Oka, D.E. Welty, S. Johnson, D.G. York, J. Dahlstrom, L.M. Hobbs, ApJ 773, 42 (2013)2) The central feature is Q-branch of a parallel band of a prolate top. (3) The radiative temperature of the environment is T_r = 2.73 K. A comparison with observed spectrum indicated that the carrier contains 5-7 heavy atoms.J. Huang, T. Oka, Mol. Phys. J.P. Maier Special Issue in press.o further strengthen this hypothesis, we have looked for vibronic satellites of the λ 5797.1 DIB. Since its anomaly toward Her 36 was ascribed to the lengthening of bonds upon the electronic excitation, vibronic satellites involving stretch vibrations are expected. Among the 73 DIBs observed toward HD 183143 to the blue of 5797.1 Å, two DIBs, λ 5545.1 and λ 5494.2 stand out as highly correlated with λ 5797.1 DIB. Their correlation coefficients 0.941 and 0.943, respectively, are not sufficiently high to establish the vibronic relation by themselves but can be explained as due to high uncertainties due to their weakness and their stellar blends. They are above the λ 5797.1 DIB by 784.0 cm⁻¹ and 951.2 cm⁻¹, respectively, approximately expected for stretching vibrations. Another observations which may possibly be explained by our hypothesis is the emission at 5800 Å from the Red Rectangle Nebula called RR 5800.G.D. Schmidt, A.N. Witt, ApJ 383, 698 (1991)ur analysis suggests that λ 5797.1 DIB and RR 5800 are consistently explained as caused by the same molecule.

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T.H. Kerr, R.E. Hibbins, S.J. Fossey, J.R. Miles, P.J. Sarre, ApJ 495, 941 (1998)W T. Oka, D.E. Welty, S. Johnson, D.G. York, J. Dahlstrom, L.M. Hobbs, ApJ 773, 42 (2013)( J. Huang, T. Oka, Mol. Phys. J.P. Maier Special Issue in press.T G.D. Schmidt, A.N. Witt, ApJ 383, 698 (1991)O

Diffuse Interstellar Bands (DIBs) are optical absorption lines observed in diffuse clouds in interstellar space. They still remain the longest standing unsolved problem in spectroscopy and astrochemistry, although several hundreds of DIBs have been already detected. Aromatic radicals in a gas phase are potential DIB candidate molecules. The electronic transitions of aromatic radicals result in optical absorption. Last year we reported the gas-phase optical absorption spectrum of the ²A₂ ← X ²B₁ transition of the thiophenoxy radical C₆H₅S using a cavity ringdown spectrometer.MF14^,Astronomical Journal

Carbonaceous compounds, both solids and gas-phase molecules, are found in very diverse astronomical mediaA.G.G.M. Tielens. Rev. Mod. Phys., 85, 1021 (2013) A significant amount of the elemental carbon is found in small dust grains. This carbonaceous dust, mostly formed in the last stages of evolution of C-rich stars, is the carrier of characteristic IR absorption bands revealing the presence of aliphatic, aromatic and olefinic functional groups in variable proportionsJ.E. Chiar, A.G.G.M. Tielens, A.J. Adamson and A. Ricca. Astrophys. J., 770, 78 (2013) Among the various candidate materials investigated as possible carriers of these bands, hydrogenated amorphous carbon (a-C:H) has led to the best agreement with the observations. Carbonaceous grains are processed by H atoms, UV radiation, cosmic rays and interstellar shocks in their passage from asymptotic giant branch stars to planetary nebulae and to the diffuse interstellar medium. The mechanisms of a-C:H production and evolution in astronomical media are presently a subject of intensive investigation. In this work we present a study of the stability of carbonaceous dust analogues generated in He+CH₄ radiofrequency discharges. In order to simulate the processing of dust in the interstellar environments, the samples have been subjected to electron bombardment, UV irradiation, and both He and H₂ plasma processing. IR spectroscopy is employed to monitor the changes in the structure and composition of the carbonaceous films.

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A.G.G.M. Tielens. Rev. Mod. Phys., 85, 1021 (2013). J.E. Chiar, A.G.G.M. Tielens, A.J. Adamson and A. Ricca. Astrophys. J., 770, 78 (2013).

In the last few years, ambitious programs were launched to probe the interstellar medium always more accurately. One of the major challenges of these missions remains the detection of prebiotic compounds and the understanding of reaction pathways leading to their formation. These complex heterogeneous reactions mainly occur on icy dust grains, and their studies require the coupling of laboratory experiments mimicking the extreme conditions of extreme cold and dilute media. For that purpose, we have developed an original experimental approach that combine the study of heterogeneous reactions (by exposing neutral molecules adsorbed on ice to non-energetic radicals H, OH, N...) and a neon matrix isolation study at very low temperatures, which is of paramount importance to isolate and characterize highly reactive reaction intermediates. Such experimental approach has already provided answers to many questions raised about some astrochemically-relevant reactions occurring in the ground state on the surface of dust grain ices in dense molecular clouds. The aim of this new present work is to show the implication of ground state atomic nitrogen on hydrogen atom abstraction reactions from some astrochemically-relevant species, at very low temperatures (3K-20K), without providing any external energy. Under cryogenic temperatures and with high barrier heights, such reactions involving N(⁴S) nitrogen atoms should not occur spontaneously and require an initiating energy. However, the detection of some radicals species as byproducts, in our solid samples left in the dark for hours at 10K, proves that hydrogen abstraction reactions involving ground state N(⁴S) nitrogen atoms may occur in solid phase at cryogenic temperatures. Our results show the efficiency of radical species formation stemming from non-energetic N-atoms and astrochemically-relevant molecules. We will then discuss how such reactions, involving nitrogen atoms in their ground states, might be the first key step towards complex organic molecules production in the interstellar medium.

Glycine, the simplest aminoacid, has been detected in comets and meteorites in our Solar System. Its detection in the interstellar medium is not improbable since other organic molecules of comparable complexity have been observedE. Herbst and E. F. van Dishoeck, Annu. Rev. Astro. Astrophys. 2009, 47:427-480 Information of how complex organic molecules resist the energetic processing that they may suffer in different regions of space is of great interest for astrochemists and astrobiologists. Further to previous investigationsB. Maté, Y. Rodriguez-Lazcano, O. Gálvez, I. Tanarro and R. Escribano, Phys Chem Chem Phys, 2011, 13, 12268. B. Maté, I. Tanarro, M.A. Moreno, M. Jiménez-Redondo, R. Escribano, and V. J. Herrero, Faraday Discussions, 2014, DOI: 10.1039/c3fd00132f.e have studied in this work, via infrared spectroscopy, the effect of 2 keV electron bombardment on amorphous and crystalline glycine layers at low temperatures, to determine its destruction cross section under astrophysical conditions. Energetic electrons are known to be present in the solar wind and in planetary magnetospheres, and are also formed in the interaction of cosmic rays with matter. Moreover, we have probed the shielding effect of water ice layers grown on top of the glycine samples at 90 K. These experiment aim to mimic the conditions of the aminoacid in ice mantles on dust grains in the interstellar medium or in some outer Solar System objects, with a water ice surface crust. A residual material, product of glycine decomposition, was found at the end of the processing. A tentative assignment of the infrared spectra of the residue will be discussed in the presentation.

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E. Herbst and E. F. van Dishoeck, Annu. Rev. Astro. Astrophys. 2009, 47:427-480. B. Maté, Y. Rodriguez-Lazcano, O. Gálvez, I. Tanarro and R. Escribano, Phys Chem Chem Phys, 2011, 13, 12268. B. Maté, I. Tanarro, M.A. Moreno, M. Jiménez-Redondo, R. Escribano, and V. J. Herrero, Faraday Discussions, 2014, DOI: 10.1039/c3fd00132f.w

The chemistry of interstellar ice analogues has been a topic of great interest to astrochemists over the last 20 years. Currently, the models of interstellar chemistry feature icy-grain reactions as a primary mechanism for the formation of many astrochemical species as well as potentially astrobiologically-relevant complex organic molecules. This talk presents new spectral results collected by a millimeter and submillimeter spectrometer coupled to a vacuum chamber designed to study the sublimation or sputtered products of icy-grain reactions initiated by thermal-processing or photo-processing of interstellar ice analogues. Initial results from thermal desorption and UV photoprocessing experiments of pure water ice and water + methanol ice mixtures will be presented.

We have previous reported at this meeting on the initial construction of a broadband (0.3 – 7.5 THz) TeraHertz time-domain spectrometer to study condensed-phase samples of astrophysically-relevant species. Here, we present the latest results from this instrument, focusing on the intersection of theory with experiment in the interpretation of our spectra. We will present both simple (CO₂) and more complex (CH₃OH and beyond) species, in their purely-crystalline and purely-amorphous states, at varying levels of matrix isolation, and as mixtures of these species. We will discuss the relative contributions of individual molecular motions (i.e. torsional modes) and bulk motions within the ice to the observed laboratory spectra. We will also touch upon the feasibility of direct interstellar detection of species from these spectra, and the results of proof-of-concept observations with the FIFI-LS instrument on the SOFIA telescope, currently scheduled for Spring 2015.

The C⁺ cation (CII) is the dominant form of carbon in diffuse clouds and an important tracer for star formation in molecular clouds. We studied the low energy deposition of C⁺ on ice using density functional theory calculations on water clusters as large as 18 H₂O. Barrierless reactions occur with water to form two dominant sets of products: HOC + H₃O⁺ and CO⁻ + 2H₃O⁺. In order to provide testable predictions, we have computed both vibrational and electronic spectra for pure ice and processed ice clusters. While vibrational spectroscopy is expected to be able to discern that C⁺ has reacted with ice by the addition of H₃O⁺ features not present in pure ice, it does not provided characteristic bands that would discern between HOC and CO⁻. On the other hand, predictions of electronic spectra suggest that low energy absorptions may occur for CO⁻ and not HOC, making it possible to distinguish one product from the other.