Institut des Sciences Moléculaires d'Orsay - UMR 8214

Le James Webb Space Telescope dévoile la face cachée de la chimie des glaces préstellaires

Martrenchard-Barra Séverine — 2023-01-23T16:11:57Z

Une équipe internationale, dont des chercheurs du CNRS - Emmanuel Dartois de l'ISMO et Jennifer Noble du PIIM - a pu mesurer la composition de glaces interstellaires dans les régions les plus sombres et les plus froides d'un nuage moléculaire mesuré à ce jour, grâce aux observations du télescope spatial James Webb (JWST) de la NASA/ESA/CSA. Ce résultat, publié dans Nature Astronomy permet aux astrophysiciens de préfigurer les molécules de glace simples qui seront potentiellement incorporées dans les futures exoplanètes, tout en ouvrant une nouvelle fenêtre sur l'origine de molécules plus complexes qui sont le point de départ pour la formation des premières briques élémentaires d'intérêt prébiotique.

Voir le Communiqué de presse de la NASA
Voir le Communiqué de presse de l'ESA

Les glaces sont un ingrédient essentiel à la construction d'une planète car elles sont de bons vecteurs d'éléments légers tels que le carbone et l'oxygène qui seront intégrés dans des atmosphères planétaires et sont à la base de la chimie des molécules prébiotiques comme les sucres, les alcools et les acides aminés simples. Dans des régions ténues de l'espace, les grains de poussière glacés offrent un cadre unique pour la rencontre des atomes et des molécules, ce qui peut promouvoir des réactions chimiques à l'origine de la formation d'espèces moléculaires.
Dans cette étude, l'équipe a ciblé les glaces enfouies dans une région particulièrement froide, dense et difficile à étudier du nuage moléculaire Chameleon I, une région située à environ 600 années-lumière de la Terre et qui est actuellement en train de former des dizaines de jeunes étoiles. L'étude a permis un inventaire détaillé des glaces les plus profondément enfouies mesurées à ce jour dans un nuage moléculaire. En plus des glaces simples comme l'eau, ainsi que des isotopes normaux et lourds du dioxyde de carbone et du monoxyde de carbone, l'équipe a pu identifier plusieurs autres espèces condensées, notamment l'anion cyanate, le sulfure de carbonyle - observé pour la première fois dans un nuage dense - et la première molécule organique considérée comme complexe dans l'espace qu'est le méthanol. Il s'agit du recensement le plus complet à ce jour des ingrédients glacés disponibles pour fabriquer les futures générations de planètes, avant qu'ils ne soient chauffés durant la formation des jeunes étoiles.

Cette recherche s'inscrit dans le cadre du projet « Ice Age », l'un des 13 programmes "Early Release Science" du JWST porté par le Dr Melissa McClure, astronome à l'Observatoire de Leiden. Ces observations sont conçues pour présenter les capacités d'observation du JWST et permettre à la communauté astronomique d'apprendre comment tirer le meilleur parti de ses instruments. L'équipe de « l'âge de glace » a déjà planifié d'autres observations, et espère retracer le parcours des glaces depuis leur formation jusqu'à l'assemblage de potentielles comètes glacées.
Cette recherche est décrite dans un article récemment publié dans la revue Nature Astronomy et fait l'objet de communiqué NASA, ESA, STSCI

Spectres de l'une des lignes de visée d'une étoile en arrière-plan du nuage du Chameleon I obtenus avec plusieurs instruments du JWST (NIRSpec et NIRCam) permettant de sonder et de faire un inventaire détaillé des glaces les plus profondément enfouies mesurées à ce jour dans un nuage moléculaire.

Cette image prise par la Near-InfraRed Camera (NIRCam) du télescope spatial James Webb de la NASA/ESA/CSA montre la région centrale du nuage moléculaire sombre Chameleon I, situé à 630 années-lumière. La matière froide et vaporeuse du nuage (bleu, centre) est éclairée dans l'infrarouge par la lueur de la jeune proto-étoile Ced 110 IRS 4 (orange, en haut à gauche). La lumière des nombreuses étoiles de fond, que l'on voit sous forme de points orange derrière le nuage, peut être utilisée pour détecter les glaces dans le nuage, qui absorbent la lumière des étoiles qui les traversent

Image Credit : NASA, ESA, CSA, and M. Zamani (ESA/Webb) ; Science : M. K. McClure (Leiden Observatory), F. Sun (Steward Observatory), Z. Smith (Open University), and the Ice Age ERS Team.

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Le JWST est un partenariat international entre la NASA, l'ESA et l'Agence spatiale canadienne (ASC).

L'équipe internationale d'astronomes participant à cette étude est composée de M. K. McClure (Leiden Observatory, Leiden University), W. R. M. Rocha (Laboratory for Astrophysics, Leiden Observatory), K. M. Pontoppidan (Space Telescope Science Institute), N. Crouzet (Leiden Observatory, Leiden University), L. E. U. Chu (NASA Postdoctoral Program Fellow, NASA Ames Research Center), E. Dartois (Institut des Sciences Moleculaires d'Orsay (ISMO), CNRS/Univ. Paris-Saclay), T. Lamberts (Leiden Institute of Chemistry, Gorlaeus Laboratories & Leiden Observatory, Leiden University), J. A. Noble (Physique des Interactions Ioniques et Moléculaires (PIIM), CNRS/Aix-Marseille Univ.), Y. J. Pendleton (Department of Physics, University of Central Florida), G. Perotti (Max Planck Institute for Astronomy), D. Qasim(Solar System Exploration Division, NASA Goddard Space Flight Center & Department of Physics and Astronomy, Howard University), M.G. Rachid (Laboratory for Astrophysics, Leiden Observatory), Z.L. Smith (School of Physical Sciences, The Open University), F. Sun (Steward Observatory, University of Arizona), Tracy L Beck (Space Telescope Science Institute), A. C. A. Boogert (Institute for Astronomy, University of Hawai'i at Manoa), W. A. Brown (Department of Chemistry, University of Sussex), P. Caselli (Max-Planck-Institut fur extraterrestrische Physik), S.B. Charnley (Solar System Exploration Division, NASA Goddard Space Flight Center), M. N. Drozdovskaya (Center for Space and Habitability, Universitaet Bern), E. Egami (Steward Observatory, University of Arizona), J. Erkal (Institute for Astronomy, University of Hawai'i at Manoa), H. Fraser (School of Physical Sciences, The Open University), R. T. Garrod (Departments of Astronomy & Chemistry, University of Virginia), D. Harsono (Institute of Astronomy, Department of Physics, National Tsing Hua University), S. Ioppolo (Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University), I. Jiménez-Serra (Centro de Astrobiología (CAB), Ctra. de Ajalvir), M. Jin (Solar System Exploration Division, NASA Goddard Space Flight Center & Department of Physics, Catholic University of America), J. K. Jørgensen (Niels Bohr Institute, University of Copenhagen), L. E. Kristensen (Niels Bohr Institute, University of Copenhagen), D.C. Lis (Jet Propulsion Laboratory, California Institute of Technology), M. R. S. McCoustra (Institute of Chemical Sciences, Heriot-Watt University), Brett A. McGuire (Department of Chemistry, Massachusetts Institute of Technology and National Radio Astronomy Observatory), G.J. Melnick (Center for Astrophysics | Harvard & Smithsonian), Karin I. Öberg (Center for Astrophysics | Harvard & Smithsonian), M. E. Palumbo (INAF - Osservatorio Astrofisico di Catania), T. Shimonishi (Faculty of Science, Niigata University), J.A. Sturm (Leiden Observatory, Leiden University), E.F. van Dishoeck (Leiden Observatory, Leiden University), and H. Linnartz (Laboratory for Astrophysics, Leiden Observatory).

Liens

• Publication :
https://www.nature.com/articles/s41550-022-01875-w (DOI : dx.doi.org/10.1038/s41550-022-01875-w)
• Communiqué de presse de l'ESA
• Communiqué de presse de la NASA
• Collection des premières images du JWST
• Brochure de l'ESA sur le JWST

International Contacts :

Melissa McClure
Leiden University, The Netherlands
Email : mcclure@strw.leidenuniv.nl

Bethany Downer
ESA/Webb Chief Science Communications Officer
E-mail : Bethany.Downer@esawebb.org

Ninja Menning
ESA Newsroom and Media Relations Office
Email : media@esa.int

Contacts français (CNRS)

Jennifer Noble
Laboratoire Physique des Interactions Ioniques et Moléculaires (PIIM), CNRS/Aix-Marseille Université, Marseille.
Email : jennifer.noble@univ-amu.fr Tel +33 (0)4 13 94 64 58

Emmanuel Dartois
Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS/Université Paris-Saclay, Orsay.
Email : emmanuel.dartois@universite-paris-saclay.fr

Le CPBM, une expertise unique en imagerie de fluorescence et une labélisation IBiSA toute récente.

Martrenchard-Barra Séverine — 2023-01-23T14:35:46Z

Cette plateforme favorise ainsi l'interaction des diverses communautés scientifiques : physique, chimie, sciences des matériaux, biologie, médecine ; et permet d'accélérer le transfert de technologies, en mettant à disposition de ses utilisateurs des équipements en microscopie mais aussi en culture cellulaire et préparation des échantillons.

Séminaire de Freek Massee (14 mars)

Martrenchard-Barra Séverine — 2023-01-22T20:57:16Z

Titre à venir

- Année 2023

Biocapteurs de bactéries à base de nanomatériaux fluorescents

2023-01-13T07:43:29Z

La détection des bactéries pathogènes est de la plus haute importance dans l'industrie alimentaire, le contrôle de la qualité de l'eau et de l'environnement, ainsi que dans le diagnostic clinique pour des raisons de santé et de sécurité. Diverses bactéries ont été identifiées comme d'importants agents pathogènes d'origine alimentaire et hydrique. La détection efficace des bactéries pathogènes exige que les méthodes d'analyse répondent à plusieurs critères exigeants avec une sensibilité élevée et des limites de détection très basses. En outre, les méthodes de détection des bactéries doivent aussi présenter une sélectivité extrêmement élevée car un très petit nombre de bactéries pathogènes coexistent souvent avec de nombreux autres micro-organismes non pathogènes. Les méthodes classiques de détection de bactéries sont souvent basées sur la culture et le dénombrement qui nécessite des temps très long avant d'obtenir les résultats. La méthode PCR, bien qu'elle rapide présentent des couts très élevés. Les biocapteurs représentent une nouvelle alternative pour permettre la détection rapide sélective à avec des très faibles seuils des bactéries. Il consiste à associer un biorécepteur qui permet de reconnaitre sélectivement la bactérie désirée avec un transducteur qui va transformer l'interaction entre le biorécepteur et la bactérie en un signal mesurable.
Le projet proposé consiste à développer des biocapteurs pour la détection de bactérie avec un système de détection présentant une lecture rapide par fluorescence dans le principe est basé sur une approche “mix and detect”(1). Les transducteurs qui seront développés seront à base de nanomatériaux organiques (porphyrines et ou phtalocyanines) qui permettent d'obtenir une fluorescence off/on suivant le phénomène de FRET. Les nanomatériaux seront modifiés avec des biorécepteurs à base de carbohydrates connus pour interagir sélectivement avec les protéines de surface de la bactérie (2). Les synthèses et modifications chimiques se feront à l'ICMMO sous la responsabilité du Dr. Hafsa Korri-Youssoufi et les caractérisations en fluorescence se feront au laboratoire ISMO sous la responsabilité du Pr. Rachel Méallet (3).

Références :

(1) Antimicrobial Activity of Cationic Poly(3-hexylthiophene) Nanoparticles Coupled with Dual Fluorescent and Electrochemical Sensing : Theragnostic Prospect, Nada Elgiddawy , Shiwei Ren, Wadih Ghattas, Waleed M. A. El Rouby, Ahmed O. El-Gendy, Ahmed A. Farghali, Abderrahim Yassar and Hafsa Korri-Youssoufi, Sensors 2021, 21, 1715 Sensors 2021, 21, 1715
(2) Dispersible Conjugated Polymer Nanoparticles as Biointerface Materials for Label-Free Bacteria Detection, Nada Elgiddawy, Shiwei Ren, Abderrahim Yassar, Alain Louis-Joseph, Hélène Sauriat-Dorizon, Waleed M.A. El Rouby, Ahmed O. El-Gendy, Ahmed A. Farghali, and Hafsa Korri-Youssoufi, ACS Appl. Mater. Interfaces 2020, 12, 36, 39979–39990
(3) Luminescence-Sensitive Surfaces Bearing Ratiometric Nanoparticles for Bacteria Growth Detection
Miaobo Pan, Gabriela Morán Cruz, Chloé Grazon, Djamila Kechkeche, Ludivine Houel Renault, Gilles Clavier, and Rachel Méallet-Renault, ACS Applied Polymer Materials 2022 4 (8), 5482-5492

Voir en ligne : Systèmes moléculaires, Astrophysique et Envrionnement

2023

2023-01-12T12:04:54Z

Peer-reviewed Publications
Aguillon, F., & Borisov, A. G. (2023). Atomic-Scale Defects Might Determine the Second Harmonic Generation from Plasmonic Graphene Nanostructures. J. Phys. Chem. Lett., 14, 238–244. Résumé: In this work, we theoretically investigate the impact of the atomic scale lattice imperfections of graphene nanoflakes on their nonlinear response enhanced by the resonance between an incident electromagnetic field and localized plasmon. As a case study, we address the second harmonic generation from graphene plasmonic nanoantennas of different symmetries with missing carbon atom vacancy defects in the honeycomb lattice. Using the many-body time-dependent density matrix approach, we find that one defect in the nanoflake comprising over five thousand carbon atoms can strongly impact the nonlinear hyperpolarizability and override the symmetry constraints. The effect reported here cannot be captured using the relaxation time approximation within the quantum or classical framework. Results obtained in this work have thus important implications for the design of nonlinear graphene devices. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML

Photoionisation spectroscopy of astrophysical free radicals in the vacuum ultraviolet spectral domain

2023-01-12T11:00:56Z

The ZEPHIRS consortium (ISMO, SOLEIL and ISM) proposes to combine the strengths of synchrotron and laser photoelectron spectroscopy for the identification of isomers/conformers of relevant reaction intermediates in atmospheric chemistry. By combining spectra with broad spectral coverage and moderate resolution, high-resolution spectra over small ranges, sophisticated ab initio calculations and dedicated models for large-amplitude motions in non-rigid molecules, novel information will be obtained on the (ro)vibronic structures of cations. These structural signatures have attractive analytical potential for reactions involving key systems such as peroxy radicals, Criegee intermediates and the C6H6 products of the propargyl reaction with itself. The results obtained will be transferred to the gas phase kinetics community for the improvement of atmospheric or combustion models.
The future candidate will participate in this project funded by the French National Research Agency (ZEPHIRS project) by working at the Institute of Molecular Sciences of Orsay on the VULCAIM set-up which couples a vacuum ultraviolet (VUV) laser with high spectral resolution and a photoelectron and/or mass spectrometer [1]. The main objective of the post-doctoral project, which is experimental in nature, will be to study the VUV photoionisation of gas phase radicals in order to obtain new data on the (ro)vibronic structure of their cations. To do this, the candidate will first work on the coupling of various radical sources with VULCAIM (electric discharge, pyrolysis, UV photolysis, fluorine reactor). He/she will carry out the acquisition of the spectra as well as their processing and simulation.

Voir en ligne : Systèmes moléculaires, Astrophysique et Environnement

Sticking of hydrogen atom on a graphene surface

2023-01-12T10:51:46Z

At the Institut des Sciences Moléculaires d'Orsay, (ISMO), within the framework of the ANR HyTRAJ project, the study of the sticking of an hydrogen atom on a graphenic surface will be studied taking into account the coupling with the vibrational modes of the substrate (phonons). The aim is to study the dynamics of collage using the quantum trajectory method developed in the ANR project.

Molecular hydrogen H2, one of the most abundant molecules in InterStellar Medium (ISM), can be formed by association of H atoms on interstellar dust grains. In our study, these grains will be modelled as graphenic surfaces. Two distinct mechanisms are usually assumed for these reactive processes : (i) two H atoms, in weak interaction with the grain (physisorption), may collide to form an H2 molecule, which is subsequently released in the gas phase ; (ii) a H atom in strong interaction with the surface (chemisorption) can react with an impinging H atom from the gas phase to form H2. In both cases, a precise determination of the probability of the first adsorption of a H atom is crucial for subsequent simulations of the H2 formation. This information, in turn, is essential in other more applied areas such as hydrogen storage [1] or graphene technology [2].
Both of the mechanisms of formation of H2 involve energy transfer between the sticking particles and the surface, thus leading to energy redistribution among the phonon bath of the substrate. Consequently, in addition to describing the motion of the reacting atoms, it is very important to accurately take into account the dissipation processes (phonon modes) induced by the nuclear degrees of freedom of the surface. The H atom interaction with a graphene surface may involve either weak dispersion interactions at large distances (physisorption) or stronger interactions at shorter distances (chemisorption). More specifically, an H atom chemisorbed on a surface C atom induces a local deformation (”puckering”) of the surface. This, in turn, translates into an activation barrier (of about 0.2 eV) for the chemisorption process. Conversely, the physisorption process is barrierless. In this respect, the sticking of an H atom on graphenic surfaces has been object of many dynamical studies (quantum, classical, and mixed quantum-classical), either in a chemisorbed state [3-7] or in a physisorbed state [8,9]. However, the simultaneous study of both chemisorbed and physisorbed states in a same calculation has not been tackled yet.
The objective of this post-doctoral position is to treat both the chemisorption and physisorption processes in a single reaction dynamics calculation, using a novel quantum-classical trajectory method. For this, we propose the calculation of the vibrational modes and couplings between the surface and the motion of the individual H atoms

[1] V. Tozzini, V. Pellegrini, Prospects for hydrogen storage in graphene, Phys. Chem. Chem. Phys., 15:80-89, 2013.
[2] M. Bonfanti, S. Achilli, R. Martinazzo, Sticking of atomic hydrogen on graphene, J. Phys. : Condens. Matter., 30:283002, 2018.
[3] S. Morisset and A. Allouche. J. Chem. Phys., 129:024509, 2008.
[4] M Bonfanti, B. Jackson, K.H. Hugues, I. Burghardt, and R. Martinazzo, Quantum dynamics of hydrogen atoms on
graphene : I. System-bath modeling, J. Chem. Phys., 143:114705, 2015.
[5] M Bonfanti, B. Jackson, K.H. Hugues, I. Burghardt, and R. Martinazzo, Quantum dynamics of hydrogen atoms on
graphene. II. Sticking, J. Chem. Phys., 143:124704, 2015.
[6] F. Karlicky, B. Lepetit, and D. Lemoine. J. Chem. Phys., 140:124702, 2014.
[7] S. Morisset, Y. Ferro, A. Allouche, J. Chem. Phys., 133:044508, 2010.
[8] B. Lepetit and B. Jackson. Phys. rev. Lett., 107:236102, 2011.
[9] B. Lepetit, D. Lemoine, Z. Medina, and B. Jackson. J. Chem. Phys., 134:114705, 2011.

Voir en ligne : Systèmes moléculaires, Astrophysique et Environnement

2023

2023-01-11T10:36:52Z

Peer-reviewed Publications
Martin-Drumel, M. - A., Zhang, Q., Doney, K. D., Pirali, O., Vervloet, M., Tokaryk, D., Western, C., Linnartz, H., Chen, Y., & Zhao, D. (2023). The bending of C3: Experimentally probing the l-type doubling and resonance. Journal of Molecular Spectroscopy, 391, 111734. Résumé: C3, a pure carbon chain molecule that has been identified in different astronomical environments, is considered a good probe of kinetic temperatures through observation of transitions involving its low-lying bending mode (ν2) in its ground electronic state. The present laboratory work aims to investigate this bending mode with multiple quanta of excitation by combining recordings of high resolution optical and infrared spectra of C3 produced in discharge experiments. The optical spectra of rovibronic (Ã1Πu−X̃1Σg+) transitions have been recorded by laser induced fluorescence spectroscopy using a single longitude mode optical parametric oscillator as narrow bandwidth laser source at the University of Science and Technology of China. 36 bands originating from X̃(0v20), v2=0−5, are assigned. The mid-infrared spectrum of the rovibrational ν3 band has been recorded by Fourier-transform infrared spectroscopy using a globar source on the AILES beamline of the SOLEIL synchrotron facility. The spectrum reveals hot bands involving up to 5 quanta of excitation in ν2. From combining analyses of all the presently recorded spectra and literature data, accurate rotational parameters and absolute energy levels of C3, in particular for states involving the bending mode, are determined. A single PGOPHER file containing all available data involving the X̃ and Ã states (literature and present study) is used to fit all the data. The spectroscopic information derived from this work enables new interstellar searches for C3, not only in the infrared and optical regions investigated here but also notably in the ν2 band region (around 63 cm−1) where vibrational satellites can now be accurately predicted. This makes C3 a universal diagnostic tool to study very different astronomical environments, from dark and dense to translucent clouds. Mots-Clés: Rovibration; Rovibronic Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Thibault, F., Viel, A., & Boulet, C. (2023). Simulation of argon induced coupling coefficients of NH3 doublets and their speed dependence. Journal of Quantitative Spectroscopy and Radiative Transfer, 296, 108453. Résumé: We present a theoretical evaluation of collision induced effects on a few typical doublets in the ν4 band of ammonia perturbed by argon. Quantum dynamical calculations performed on two NH3-Ar potential energy surfaces provide pressure broadening and intradoublet generalized cross sections. From these calculations we derive thermally averaged values at various temperatures. The intradoublet coupling terms at room temperature are found to be in good agreement with available data in the literature. In addition, we study the speed dependence of the pressure broadening and intradoublet coupling coefficients. The former show a usual speed dependence, quite important, but the later show a weak speed dependence at least around 296 K and above. Mots-Clés: Ammonia; NH-Ar; Collisional Broadening; Line Mixing; Speed Dependence; Quantum Dynamical Calculations Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML

Publications

2023-01-09T12:52:35Z

Peer-reviewed Publications
Aguillon, F., & Borisov, A. G. (2023). Atomic-Scale Defects Might Determine the Second Harmonic Generation from Plasmonic Graphene Nanostructures. J. Phys. Chem. Lett., 14, 238–244. Résumé: In this work, we theoretically investigate the impact of the atomic scale lattice imperfections of graphene nanoflakes on their nonlinear response enhanced by the resonance between an incident electromagnetic field and localized plasmon. As a case study, we address the second harmonic generation from graphene plasmonic nanoantennas of different symmetries with missing carbon atom vacancy defects in the honeycomb lattice. Using the many-body time-dependent density matrix approach, we find that one defect in the nanoflake comprising over five thousand carbon atoms can strongly impact the nonlinear hyperpolarizability and override the symmetry constraints. The effect reported here cannot be captured using the relaxation time approximation within the quantum or classical framework. Results obtained in this work have thus important implications for the design of nonlinear graphene devices. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
D. Bresteau, C. Spezzani, O. Tcherbakoff, J.-F. Hergott, F. Lepetit, P. D'Oliveira, P. Salieres, R. Geneaux, M. Luttmann, I. Vadillo-Torre, J. Lenfant, S. J. Weber, M. Dehlinger, E. Meltchakov, F. Delmotte, C. Bourassin-Bouchet, J. Im, Z. Chen, J. Caillaux, J. Zhang, M. Marsi, L. Barreau, L. Poisson, D. Dowek, M. Fanciulli, O. Heckmann, M. C. Richter, K. Hricovini, M. Sebdaoui, D. Dennetiere, F. Polack, & T. Ruchon. (2023). FAB10: a user-oriented bandwidth-tunable extreme ultraviolet lightsource for investigations of femtosecond to attosecond dynamics in gas and condensed phases. Eur. Phys. J. Spec. Top., . Résumé: We present the commissioning of the FAB10 beamline (Femtosecond to Attosecond Beamline at 10 kHz repetition rate) that has been developped and operated in the last few years at the ATTOLab facility of Paris-Saclay University. Based on the high harmonic generation process, the beamline is dedicated to investigations of ultrafast dynamics in a broad variety of systems ranging from gas phase to condensed matter in pump-probe arrangements. Its design and operation has been strongly influenced by both the laser and the large scale instruments communities, which makes it unique in several aspects. In particular, it is possible to tune the extreme ultraviolet (XUV, 10–100 eV) bandwidth from 0.2 to 20 eV – with corresponding pulse duration from 30 to 0.3 femtoseconds (fs) – thanks to an original and fully automated XUV spectral filter with three operation modes. After a general overview of the beamline features, each of those operation modes is described, characterized and illustrated with commissioning experiments. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Imani, Z., Mundlapati, V. R., Brenner, V., Gloaguen, E., Le Barbu-Debus, K., Zehnacker, A., Robin, S., Aitken, D. J., & Mons, M. (2023). Non-covalent interactions reveal the protein chain δ conformation in a flexible single-residue model. ChemComm, . Résumé: The δ conformation is a local secondary structural feature in proteins that implicates a πamide N-H···N interaction between a backbone N atom and the NH of the following residue. Small molecule probes of this conformation have been limited so far to rigid proline-type models that may over-emphasize the significance of the interaction. We show here that, in thiacyclic amino acid derivatives with a sulphur atom in the γ-position, specific side-chain/backbone N-H···S interactions stabilize the δ conformation sufficiently to allow it to compete with classical C5 and C7 H-bonding conformers. With support from quantum chemistry, the δ-folded conformers have been characterized by IR spectroscopy in the gas phase. In solution, the IR absorption of the πamide N-H appears at 3450 cm-1, notably less red-shifted than in proline-type models, in a frequency range often considered as implicating a free NH motif and suggestive of very weak hydrogen bonding at best. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Martin-Drumel, M. - A., Zhang, Q., Doney, K. D., Pirali, O., Vervloet, M., Tokaryk, D., Western, C., Linnartz, H., Chen, Y., & Zhao, D. (2023). The bending of C3: Experimentally probing the l-type doubling and resonance. Journal of Molecular Spectroscopy, 391, 111734. Résumé: C3, a pure carbon chain molecule that has been identified in different astronomical environments, is considered a good probe of kinetic temperatures through observation of transitions involving its low-lying bending mode (ν2) in its ground electronic state. The present laboratory work aims to investigate this bending mode with multiple quanta of excitation by combining recordings of high resolution optical and infrared spectra of C3 produced in discharge experiments. The optical spectra of rovibronic (Ã1Πu−X̃1Σg+) transitions have been recorded by laser induced fluorescence spectroscopy using a single longitude mode optical parametric oscillator as narrow bandwidth laser source at the University of Science and Technology of China. 36 bands originating from X̃(0v20), v2=0−5, are assigned. The mid-infrared spectrum of the rovibrational ν3 band has been recorded by Fourier-transform infrared spectroscopy using a globar source on the AILES beamline of the SOLEIL synchrotron facility. The spectrum reveals hot bands involving up to 5 quanta of excitation in ν2. From combining analyses of all the presently recorded spectra and literature data, accurate rotational parameters and absolute energy levels of C3, in particular for states involving the bending mode, are determined. A single PGOPHER file containing all available data involving the X̃ and Ã states (literature and present study) is used to fit all the data. The spectroscopic information derived from this work enables new interstellar searches for C3, not only in the infrared and optical regions investigated here but also notably in the ν2 band region (around 63 cm−1) where vibrational satellites can now be accurately predicted. This makes C3 a universal diagnostic tool to study very different astronomical environments, from dark and dense to translucent clouds. Mots-Clés: Rovibration; Rovibronic Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Thibault, F., Viel, A., & Boulet, C. (2023). Simulation of argon induced coupling coefficients of NH3 doublets and their speed dependence. Journal of Quantitative Spectroscopy and Radiative Transfer, 296, 108453. Résumé: We present a theoretical evaluation of collision induced effects on a few typical doublets in the ν4 band of ammonia perturbed by argon. Quantum dynamical calculations performed on two NH3-Ar potential energy surfaces provide pressure broadening and intradoublet generalized cross sections. From these calculations we derive thermally averaged values at various temperatures. The intradoublet coupling terms at room temperature are found to be in good agreement with available data in the literature. In addition, we study the speed dependence of the pressure broadening and intradoublet coupling coefficients. The former show a usual speed dependence, quite important, but the later show a weak speed dependence at least around 296 K and above. Mots-Clés: Ammonia; NH-Ar; Collisional Broadening; Line Mixing; Speed Dependence; Quantum Dynamical Calculations Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML

Soutenance d'HDR de Minh-Huong Ha-Thi (18 janvier)

Martrenchard-Barra Séverine — 2023-01-09T10:49:06Z

Etude des processus photoinduits de systèmes moléculaires pour la conversion de l'énergie solaire.

L'énergie solaire peut être transformée en énergie électrique par les processus photovoltaïques ou en énergie chimique par photocatalyse. La conversion de l'énergie solaire implique plusieurs processus : absorption de la lumière, séparation et/ou accumulation de charges, collection de charges sur les électrodes en cellule photovoltaïque ou catalyse des réactions d'oxydo-réduction en photocatalyse. Les processus photoinduits comme le transfert d'électron photoinduit ou le transfert d'énergie jouent un rôle essentiel pour comprendre et améliorer le rendement de la conversion de l'énergie. La compréhension fondamentale de ces processus par des techniques spectroscopiques nous permettra de lever la voile sur les facteurs limitants et de concevoir des photosystèmes plus efficaces.
L'objectif de mes recherches est d'étudier ces processus fondamentaux, en particulier les processus de transfert de charge et d'accumulation de charges dans des systèmes moléculaires. Plusieurs montages spectroscopiques ont été développés et utilisés comme absorption transitoire et Raman résonnant pompe-pompe-sonde avec deux faisceaux d'excitation synchronisés. Plusieurs systèmes moléculaires sont considérés : les dyades et triades donneur-accepteur, les photocatalyseurs à base de porphyrines ou polyoxométallates. Quelques résultats marquants sont présentés sur la compréhension du chemin de relaxation des photosystèmes étudiés, avec une attention particulière sur les processus de transfert et d'accumulation de charges.

Composition du Jury :

Pellegrin, Yann, Directeur de recherche au CNRS, CEISAM, Nantes
Charvarot-Kerlidou, Murielle, Directrice de recherche au CNRS, Laboratoire de Chimie et Biologie des Métaux, CEA Grenoble
Haacke, Stefan, Professeur à l'IPCMS et Télécom Physique Strasbourg, Institut de Physique et Chimie des Matériaux de Strasbourg
Remita, Hynd, Directrice de recherche au CNRS, ICP UMR 8000 CNRS, Université Paris-Saclay
Wenger, Oliver, Professeur, University of Basel, Department of Chemistry
Chauvin, Jérôme, Maître de conférences à l'Université Grenoble Alpes, Département de Chimie Moléculaire UMR 5250 CS 40700

Peer-reviewed Publications
Aguillon, F., & Borisov, A. G. (2023). Atomic-Scale Defects Might Determine the Second Harmonic Generation from Plasmonic Graphene Nanostructures. J. Phys. Chem. Lett., 14, 238–244. Résumé: In this work, we theoretically investigate the impact of the atomic scale lattice imperfections of graphene nanoflakes on their nonlinear response enhanced by the resonance between an incident electromagnetic field and localized plasmon. As a case study, we address the second harmonic generation from graphene plasmonic nanoantennas of different symmetries with missing carbon atom vacancy defects in the honeycomb lattice. Using the many-body time-dependent density matrix approach, we find that one defect in the nanoflake comprising over five thousand carbon atoms can strongly impact the nonlinear hyperpolarizability and override the symmetry constraints. The effect reported here cannot be captured using the relaxation time approximation within the quantum or classical framework. Results obtained in this work have thus important implications for the design of nonlinear graphene devices. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
D. Bresteau, C. Spezzani, O. Tcherbakoff, J.-F. Hergott, F. Lepetit, P. D'Oliveira, P. Salieres, R. Geneaux, M. Luttmann, I. Vadillo-Torre, J. Lenfant, S. J. Weber, M. Dehlinger, E. Meltchakov, F. Delmotte, C. Bourassin-Bouchet, J. Im, Z. Chen, J. Caillaux, J. Zhang, M. Marsi, L. Barreau, L. Poisson, D. Dowek, M. Fanciulli, O. Heckmann, M. C. Richter, K. Hricovini, M. Sebdaoui, D. Dennetiere, F. Polack, & T. Ruchon. (2023). FAB10: a user-oriented bandwidth-tunable extreme ultraviolet lightsource for investigations of femtosecond to attosecond dynamics in gas and condensed phases. Eur. Phys. J. Spec. Top., . Résumé: We present the commissioning of the FAB10 beamline (Femtosecond to Attosecond Beamline at 10 kHz repetition rate) that has been developped and operated in the last few years at the ATTOLab facility of Paris-Saclay University. Based on the high harmonic generation process, the beamline is dedicated to investigations of ultrafast dynamics in a broad variety of systems ranging from gas phase to condensed matter in pump-probe arrangements. Its design and operation has been strongly influenced by both the laser and the large scale instruments communities, which makes it unique in several aspects. In particular, it is possible to tune the extreme ultraviolet (XUV, 10–100 eV) bandwidth from 0.2 to 20 eV – with corresponding pulse duration from 30 to 0.3 femtoseconds (fs) – thanks to an original and fully automated XUV spectral filter with three operation modes. After a general overview of the beamline features, each of those operation modes is described, characterized and illustrated with commissioning experiments. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Imani, Z., Mundlapati, V. R., Brenner, V., Gloaguen, E., Le Barbu-Debus, K., Zehnacker, A., Robin, S., Aitken, D. J., & Mons, M. (2023). Non-covalent interactions reveal the protein chain δ conformation in a flexible single-residue model. ChemComm, . Résumé: The δ conformation is a local secondary structural feature in proteins that implicates a πamide N-H···N interaction between a backbone N atom and the NH of the following residue. Small molecule probes of this conformation have been limited so far to rigid proline-type models that may over-emphasize the significance of the interaction. We show here that, in thiacyclic amino acid derivatives with a sulphur atom in the γ-position, specific side-chain/backbone N-H···S interactions stabilize the δ conformation sufficiently to allow it to compete with classical C5 and C7 H-bonding conformers. With support from quantum chemistry, the δ-folded conformers have been characterized by IR spectroscopy in the gas phase. In solution, the IR absorption of the πamide N-H appears at 3450 cm-1, notably less red-shifted than in proline-type models, in a frequency range often considered as implicating a free NH motif and suggestive of very weak hydrogen bonding at best. Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Martin-Drumel, M. - A., Zhang, Q., Doney, K. D., Pirali, O., Vervloet, M., Tokaryk, D., Western, C., Linnartz, H., Chen, Y., & Zhao, D. (2023). The bending of C3: Experimentally probing the l-type doubling and resonance. Journal of Molecular Spectroscopy, 391, 111734. Résumé: C3, a pure carbon chain molecule that has been identified in different astronomical environments, is considered a good probe of kinetic temperatures through observation of transitions involving its low-lying bending mode (ν2) in its ground electronic state. The present laboratory work aims to investigate this bending mode with multiple quanta of excitation by combining recordings of high resolution optical and infrared spectra of C3 produced in discharge experiments. The optical spectra of rovibronic (Ã1Πu−X̃1Σg+) transitions have been recorded by laser induced fluorescence spectroscopy using a single longitude mode optical parametric oscillator as narrow bandwidth laser source at the University of Science and Technology of China. 36 bands originating from X̃(0v20), v2=0−5, are assigned. The mid-infrared spectrum of the rovibrational ν3 band has been recorded by Fourier-transform infrared spectroscopy using a globar source on the AILES beamline of the SOLEIL synchrotron facility. The spectrum reveals hot bands involving up to 5 quanta of excitation in ν2. From combining analyses of all the presently recorded spectra and literature data, accurate rotational parameters and absolute energy levels of C3, in particular for states involving the bending mode, are determined. A single PGOPHER file containing all available data involving the X̃ and Ã states (literature and present study) is used to fit all the data. The spectroscopic information derived from this work enables new interstellar searches for C3, not only in the infrared and optical regions investigated here but also notably in the ν2 band region (around 63 cm−1) where vibrational satellites can now be accurately predicted. This makes C3 a universal diagnostic tool to study very different astronomical environments, from dark and dense to translucent clouds. Mots-Clés: Rovibration; Rovibronic Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML
Thibault, F., Viel, A., & Boulet, C. (2023). Simulation of argon induced coupling coefficients of NH3 doublets and their speed dependence. Journal of Quantitative Spectroscopy and Radiative Transfer, 296, 108453. Résumé: We present a theoretical evaluation of collision induced effects on a few typical doublets in the ν4 band of ammonia perturbed by argon. Quantum dynamical calculations performed on two NH3-Ar potential energy surfaces provide pressure broadening and intradoublet generalized cross sections. From these calculations we derive thermally averaged values at various temperatures. The intradoublet coupling terms at room temperature are found to be in good agreement with available data in the literature. In addition, we study the speed dependence of the pressure broadening and intradoublet coupling coefficients. The former show a usual speed dependence, quite important, but the later show a weak speed dependence at least around 296 K and above. Mots-Clés: Ammonia; NH-Ar; Collisional Broadening; Line Mixing; Speed Dependence; Quantum Dynamical Calculations Lien permanent \| Sauvegarder la référence: RTF PDF LaTeX \| Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML

Institut des Sciences Moléculaires d'Orsay - UMR 8214

Le James Webb Space Telescope dévoile la face cachée de la chimie des glaces préstellaires

Le CPBM, une expertise unique en imagerie de fluorescence et une labélisation IBiSA toute récente.

Séminaire de Freek Massee (14 mars)

Biocapteurs de bactéries à base de nanomatériaux fluorescents

2023

Peer-reviewed Publications

Photoionisation spectroscopy of astrophysical free radicals in the vacuum ultraviolet spectral domain

Sticking of hydrogen atom on a graphene surface

2023

Peer-reviewed Publications

Publications

Peer-reviewed Publications

Soutenance d'HDR de Minh-Huong Ha-Thi (18 janvier)

Etude des processus photoinduits de systèmes moléculaires pour la conversion de l'énergie solaire.