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Submillimeterwave Spectroscopy and Ism Search for Propionic Acid

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Submillimeterwave Spectroscopy and Ism Search for Propionic Acid SUBMILLIMETERWAVE SPECTROSCOPY AND ISM SEARCH FOR PROPIONIC ACID L. Margulès1, R. A. Motiyenko1, V.V. Ilyushin2, O. Dorovskaya2, E.A. Alekseev2, E. R. Alonso3, L. Kolesniková3, J. Cernicharo4, and J.C. Guillemin5 1Laboratoire PhLAM UMR8523,Université de Lille, France 2Institute of Radio Astronomy of NASU, Kharkiv, Ukraine 3Lab. de Espectroscopica y Bioespectroscopica, Universidad de Valladolid, Spain 4Molecular Astrophysics, ICMM, Madrid, Spain 5Institut des Sciences Chimiques de Rennes, ENSCR, France L. Margulès et al, 74TH International Symposium on Molecular Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS C3H6O2 isomers Relative energy kj.mol-1 cm-1 propanoic acid 0.00 0.00 methyl acetate (ISM) 29.20 2440.56 ethyl formate (ISM) 48.86 4083.98 lactaledehyde 106.32 8887.84 metoxy acetaldehyde 151.31 12648.32 Ethenoxymethanol 157.65 13178.79 1,3 diooxolane 2 159.24 13311.79 C3H6O2 isomers in ISM • Ethyl formate EtOC(O)H • Methyl acetate CH3OC(O)CH3 L. Margulès et al, 74TH International Symposium on Molecular 3 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Previous studies • MW Double resonnance up to 40 GHz (O. Stiefvater, J. Chem. Phys. 62, 244, 1975) • FTMW measurements up to 18 GHz (B. Ouyang et al, J. Phys. Chem. A 112, 8208, 2008) ma= 0.19 D mb= 1.53 D mc= 0.00 D -1 V3=810.7(37) cm Main difficulty is a low vibration bending mode at 35cm-1 L. Margulès et al, 74TH International Symposium on Molecular 4 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Fast DDS Lille’s spectrometer DDS-based synthesizer allows very fast frequency switching with high resolution and continuous phase • Fast decade spanning spectrometer:0.15-1.5 THz • Less than 24h is needed at high resolution (Doppler limited) and sensitivity to record the all range • Typical: Acq. time 1ms/point On going developpment: emission spectroscopy (L. Zou FB04) L. Margulès et al, 74TH International Symposium on Molecular 5 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Potential function in internal rotation V3 V6 Methyl group is C3v symmetry : V(a) = (1- cos3a)+ (1- cos6a)+... S 2 2 • Due to tunnel effect, the transitions are splitted into 2 E 1 - 2 A two components: A and E 1 1 A - 1 E •The code used in these cm Energy in Energy in cm studies is RAM36-code from 786 = 0 E 3 V. Ilyushin which include V 0 A terms up to 12th order. The code could treat V case, Torsional angle 6 in degree used for toluene study (V. Ilyushin et al. J. Mol. Spectrosc 259, 26, 2010). L. Margulès et al, 74TH International Symposium on Molecular 6 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Propionic acid results RAM axis system this work A (GHz) 9.8430(28) B (GHz) 4.0667(26) C (GHz) 2.86781(11) F (GHz) 165.857 (fixed) r 0.05206(14) 1 V3 (cm- ) 786.04(34) 2Dab (GHz) -2643(12) FMAX 550GHz Nparam/Nlines 20/2530 Rms/wrms 56 kHz/0.86 L. Margulès et al, 74TH International Symposium on Molecular 7 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS ISM search • No detection of propionic acid in : . Orion (30m and ALMA) . SgrB2 (public data from Belloche) . SGrB2 PRIMOS) . dark clouds surveys . 30m data of IRAS16923 . 12m NRAO data of W51. • upper limits and comparaison with the abundances of the other conformers will be given in the future paper L. Margulès et al, 74TH International Symposium on Molecular 8 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS ISM search • Why no detection? • Methyl formate is one of the major exception of Minimum Energy principle (Lattelais et al, ApJ, 696, L133, 2009) : adsorption of acid on the grains • Formate could be favored as methyl formate is much more abundant that acetic acid • The reason could be link to the way CO2 on ice grains hydrogenate and methylate • methylisation of CO2 is a possible route to form CH3COOCH3 L. Margulès et al, 74TH International Symposium on Molecular 9 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS From Laboratory to Interstellar medium: « It is a long way to the top » R.A. Motiyenko, PCCP, 2018,20, 5509 - B. A. Mc Guirre et al. 2018, ApJL, 851, 2 L. Margulès et al, 74TH International Symposium on Molecular 10 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Target’s choice • Definition of targets follow mainly the 3 following pathways and is based on detected molecules • Going to next complexity • replacing atom (O with S for exemple), groups,… • isomers of detected molecules L. Margulès et al, 74TH International Symposium on Molecular 11 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS From Laboratory to Interstellar medium: « It is a long way to the top » 1) Target discussions between astronomers, chimists and spectroscopists (yes it is sure, it will be detected in ISM….) 2) Sample availibility (not fun if this is commercialy available, why we miss propylene oxide CH3CHCH2O) 3) Measurements of the spectra (easier with fast spectrometer) 4) Analysis of the spectra : from hours to months…. not only because spectrosocpits are lazy, large amplitude motion make analysis difficult most of the time! (easier with broadband spectrometer) FAST+BRAODBAND : Lille’s fast scan DDS spectrometer 5) Accurate predictions provided: interpolation only, no extrapolation 6) Detection or not... In very few cases detection could be in ISM prior to lab (example : NS+, Cernicharo et al., 2018, ApJL, 853, 2) L. Margulès et al, 74TH International Symposium on Molecular 12 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Molecules detected « recently » Acetaldehyde-D We report the first detection of CH2DCOH (93 transitions) and the detection of CH3COD (43 transitions) species in IRAS 16293-2422 using the publicly available ALMA PILS L. Margulès et al, 74TH International Symposium on Molecular 13 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Ethyl cyanide CH3CH2CN isotopologues Ethyl cyanide, also known as propanenitrile or propionitrile, has been observed in abundance in hot molecular clouds in the range 40–950 GHz (1st ISM detection: Johnson, D. R., et al. 1977, ApJ, 218, 370) 13C detection 15N detection 1st detection of doubly no detection subtitled 13C -1 -1 Excited vibrational state study (vbending = 206 cm and vtorsion = 213 cm ) of 13C species in collaboration with JPL (B. Drouin‘s group) L. Margulès et al, 74TH International Symposium on Molecular 14 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Formamide NH2CO - D • Formamide (HCONH2) is the simplest molecule with a peptide bond detected in the interstellar medium (Rubin, R. H., et al. 1971, ApJ, 169, L39) • it has been shown that of all possible simplest interstellar molecules that contain a peptide bond, formamide is the most stable energetically (Lattelais, et al. 2010, A&A, 519, A30 ) −1 • ν12 = 289 cm . All other excited vibrational states lie above 500 cm−1 • 13C also measured in this work L. Margulès et al, 74TH International Symposium on Molecular 15 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS N-methylformamide: CH3NHCHO • structural isomer of the known interstellar molecule acetamide, CH3C(O)NH2 • Both molecules contain a peptide bond which is the characteristic chemical bond linking amino acids in proteins • N-methylformamide can also be seen as a partially hydrogenated form of methyl isocyanate, CH3NCO, which was recently detected in the ISM • Internal rotation motion with very low barrier value: 55.17 cm-1 • The spectra was measured from 45 to 660 GHz • The analysis is carried out using the 16 Rho-axis method and the RAM36 code NS+ L. Margulès et al, 74TH International Symposium on Molecular 17 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Hydroxyacetonitrile (HOCH2CN) • Compete with aminomethanol (NH2CH2OH), a glycine precursor, through the Strecker synthesis (Danger G. et al., ApJ 756, 11, 2012) • Its photochemistry leads to the formation of formylcyanide (CHOCN), ketenimine (CH2CNH), formaldehyde (CH2O), hydrogen cyanide (HCN), carbon monoxyde (CO) (Danger G. et al. A&A 549, A93, 2012) • Detection of aminoacetonitrile in SgrB2(N) (NH2CH2CN) (A. Belloche, et al. A&A, 2008, 482 179) Methyl isocyanate (CH3NCO) the most stable energetically structural isomer was detected BREAKING NEWS detection in IRAS 16293 18 Lot of non detections Di-cyanomethane (malonitrile-NC-CH2-CN) and isocyanomethane • Following the first microwave study of a bis-isocyanide derivative diisocyanomethane (Motiyenko et al., A&A 2012, 544 A82) • No MW study about the cyano-isocyanomethane (CNCH2CN). • the most stable isomer malonitrile also reinvistigated: • Study is limited to 240 GHz (Burie et al. 1982, J. Phys. 43, 1319) • Spin statistic we put in evidence in the diisocyanomethane study was not took into account. Acetyl isocyanate (CH3CONCO)+CH3ONCO • Isocyanic acid, HNCO, was among the very early molecules to be detected in space • OCN- is assumed to be in the grains (K. Demyk et al. A&A, 339 (1998), 553) • CH3COCH3 is detected since 1987 Sgr B2 (F. Combes et al. A&A, 180, (1987), L13) • CH3O detected in B1-b (Cernicharo et al. 2012, ApJ, 759, L43) • NCO in L483 (Marcelino et al.,2018, A&A, L10 L. Margulès et al, 74TH International Symposium on Molecular 19 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Ethyl-isocyanide (CH3CH2NC) • The few isocyanides detected in the ISM are always isomers of the corresponding : HNC, CH3NC, HCCNC • Isocyanides molecules are poorly studied mainly due Spectroscopy of isocyanides is often complicated by difficulties in synthesis and kinetic instability of many of them • Ethyl-iscocyanide (CH3CH2NC) is isomer of one of the most abundant Complex Organic Molecules • Very badly surprised with the non detection L. Margulès et al, 74TH International Symposium on Molecular 20 Spectroscopy, JUNE 17-21, 2019 - CHAMPAIGN-URBANA, ILLINOIS Aminomalononitrile : H2NCH(CN)2 • HCN trimer (trimer of the key molecule for 15N fractionation) • AMN is a useful intermediate in the synthesis of many heterocyclic systems.
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