Study of aerosols precursors and their hydrates from microwave and infrared spectroscopy supported by quantum chemistry calculations

Title and thesis summary

Study of aerosols precursors and their hydrates from microwave and infrared spectroscopy supported by quantum chemistry calculations

The formation of aerosols in the atmosphere follows very complex chemical processes that have not been clarified so far. To facilitate atmospheric studies, laboratory spectroscopy at the molecular level is a tool of choice.
In this context, we have combined quantum chemistry calculations with molecular high resolution spectroscopy in order to study the structures of trans − methylglyoxal: a possible precursor of secondary organic aerosols AOS. This study allows, in a first step, to record and model the rotation spectra of the isolated molecule CH3COCHO.Evently, it allows to generate useful set of spectroscopic ground state parameters for the Infrared study that covers the atmospheric spectral range. In a second step, the same study can be applied to the molecule in the presence of the water in order to specify the position of the hydration sites (CH3COCHO-H2O) as well as the degradation products (gemi−diol and tetrol). These data are very useful for the quantification of molecules for the simulations of the phenomena such as nucleation. These molecules have in their structures the methyl group. Therefore, a large amplitude motion, the internal rotation of the methyl group, leads to a splitting of the lines. The spectrum modeling in this case is done with specific codes in order to reproduce their spectra at experimental accuracy and to determine a set of spectroscopic parameters with very high precision.

The second part consists in studying the dimer of the simple carboxylic acid (formic acid dimer) (HCOOH)2 known for its abundance. This centro-symmetric molecule does not possess a spectrum of rotation. In this manuscript, we analyze the rovibrational spectrum recorded at high resolution by means of the Jet−AILES equipment coupled to infrared light AILES of synchrotron (Soleil). This molecule also exhibits a large amplitude motion (proton exchange) which makes the analysis of spectra more complex.

Thesis supervisor(s): Thérèse Huet – Manuel Goubet
Referees: Vincent Boudon – Isabelle Kleiner
Examiners: Arnaud Cuisset – Pascale Soulard

Laboratory : PhLAM

Financing : Région Nord-Pas-de-Calais / Labex CaPPA

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Publications

Millimeter wave spectra of carbonyl cyanide. S.B. Bteich, B. Tercero, J. Cernicharo, R.A. Motiyenko, L. Margulès, and J.-C. Guillemin. Astronomy & Astrophysics, volume 592, A43, 2016, DOI: https://doi.org/10.1051/0004-6361/201628379

Vibrational Dynamic and Spectroscopic Molecular Parameters of Trans-Methylglyoxal, a Gaseous Precursor of Secondary Organic Aerosols. S. Bteich, M. Goubet , R. A. Motiyenko , L. Margulès, T. R. Huet.
J. Mol. Spec. 2017, DOI: https://doi.org/10.1016/j.jms.2017.12.007

Towards the detection of explosive taggants: microwave and millimetre-wave gas phase spectroscopies of 3-Nitrotoluene. A. Roucou , I. Kleiner, M. Goubet , S.Bteich, G. Mouret, R. Bocquet, F. Hindle, W.L. Meerts, A. Cuisset
chemphyschem, Janvier 2018, DOI: 10.1002/cphc.201701266

Oral and posters presentation

Oral Presentations

Spectroscopic study of Methylglyoxal and its hydrates: a gaseous precursor of secondary organic aerosols. S. Bteich, M. Goubet, R. A. Motyienko, L. Margulès, T. H. Huet. ISMS June 2016 Champaign – Urbana, Illinois

Internal  rotation  potential  and  pure  rotational  spectroscopy  of  3-nitrotoluene,  A.  Roucou,  I.  Kleiner,  S.  Bteich,  M.  Goubet,  G. Mouret, F. Hindle, R. Bocquet, W. L. Meerts, and A. Cuisset.  9th THz Days, Dunkerque, France, 12/06/17 – 15/06/17.

Internal  rotation  potential  and  pure  rotational  spectroscopy  of  3-nitrotoluene,  A.  Roucou,  I.  Kleiner,  S.  Bteich,  M.  Goubet,  G. Mouret,  F.  Hindle,  R.  Bocquet,  W.  L.  Meerts,  and  A.  Cuisset.   SPECMO – 2017 Plenary Meeting – Young Researchers Forum, Université Lille 1, Villeneuve d’Ascq,22/05/17 – 23/02/17.

Internal rotation potential and pure rotational spectroscopy of 3-nitrotoluene. A. Roucou, A. Cuisset,  G. Mouret, F. Mouret, F. Hindle,  R.  Bocquet,  D.  Sadovskii,  I.  Kleiner,  M.  Goubet.  S.  Bteich,  W.  L.  Meerts.   International Conference on High Resolution Molecular Spectroscopy 2016, Prague, 30/08/16 – 3/09/16

Poster presentations

Congrès international ICAC Villeneuve d’Ascq (21-23 Mars 2017) Rotational Spectroscopy of trans_Methylglyoxal,and its hydrates Sabath BTEICH, Manuel GOUBET, Roman A. MOTIYENKO, Laurent MARGULES et Thérèse R. HUET, présenté 28 Aout 2017. photo ci-contre

Pure rotational spectroscopy of 3-nitrotoluene: a case of very low-barrier for internal rotation.  A. Roucou, A. Cuisset, G. Mouret, F.  Hindle,  R.  Bocquet,  I. Kleiner,  M.  Goubet,  S.  Bteich,  L.  Meerts. The  25th  International  Colloquium  of  High  Resolution Molecular Spectroscopy, Helsinki, Finland, 20/08/17 – 25/08/17.

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Future

Looking for opportunities
–> contact Sabath BTEICH

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