A5084325757- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Astrophysics and Star Formation Studies
- Photochemistry and Electron Transfer Studies
- Atmospheric chemistry and aerosols
- Astro and Planetary Science
- Spectroscopy and Quantum Chemical Studies
- Inorganic Fluorides and Related Compounds
- Photochromic and Fluorescence Chemistry
- Photocathodes and Microchannel Plates
- Synthesis and Properties of Aromatic Compounds
- Fullerene Chemistry and Applications
- Astronomy and Astrophysical Research
- Various Chemistry Research Topics
- Astronomical Observations and Instrumentation
- Catalysis and Oxidation Reactions
- Chemical Reactions and Mechanisms
- Advanced Frequency and Time Standards
- Analytical Chemistry and Chromatography
- Solar and Space Plasma Dynamics
- Thermodynamic properties of mixtures
Université Paris-Saclay
2021-2025
Centre National de la Recherche Scientifique
2012-2025
Institut des Sciences Moléculaires d'Orsay
2012-2025
Centre National pour la Recherche Scientifique et Technique (CNRST)
2025
The University of Melbourne
2018-2022
ETH Zurich
2013-2019
Charles Humbert 8
2017
Université Paris-Sud
2012
Argonne National Laboratory
2012
Carbon aggregates containing between 10 and 30 atoms preferentially arrange themselves as planar rings. To learn more about this exotic allotrope of carbon, electronic spectra are measured for even cyclo[n]carbon radical cations (C14+-C36+) using two-color photodissociation action spectroscopy. eliminate spectral contributions from other isomers, the target isomer-selected a drift tube ion mobility spectrometer prior to spectroscopic interrogation. The exhibit sharp transitions spanning...
The C3H+ cation plays a pivotal role within the chemical network of dense interstellar clouds. Its relatively slow reaction with molecular hydrogen (H2) suggests that reactions other species, particularly small hydrocarbons, may play significant role. In this study, we measured absolute cross sections acetylene (C2H2) and two isomers C3H4 (allene propyne). To facilitate implementation our experimental data into astrochemical models, converted rate constants. No temperature dependency was...
Infrared (IR) cooling of polycyclic aromatic hydrocarbon (PAH) molecules is a major radiative stabilization mechanism PAHs present in space and the origin infrared bands (AIBs). Here, we report an anharmonic cascade model master equation framework to IR emission rates spectra energized as function internal energy. The underlying (simple harmonic cascade) for fundamental vibrations has been developed through modeling PAH cations other carboneaous ions measured electrostatic ion storage ring...
The methylidyne cation (CH^+) and the methyl (CH_3^+) are building blocks of organic molecules in ultraviolet (UV)-irradiated gas, yet their coupled formation excitation mechanisms mostly remain unprobed. James Webb Space Telescope (JWST), with its high spatial resolution good spectral resolution, provides unique access to detection these molecules. Our goal is use first CH^+ CH_3^+ infrared rovibrational emission Orion Bar protoplanetary disk d203-506 probe constrain physico-chemical...
Context. The methyl cation (CH 3 + ) has recently been discovered in the interstellar medium through detection of 7 μm (1400 cm −1 features toward d203-506 protoplanetary disk by JWST. Line-by-line spectroscopic assignments these features, however, were unsuccessful due to complex intramolecular perturbations preventing a determination excitation and abundance species that source. Aims. Comprehensive rovibrational guided theoretical experimental laboratory techniques provide insight into...
Resonant Auger processes provide a unique perspective on electronic interactions and excited vibrational states of molecular ions. Here, new data are presented the resonant decay CH3I in region just below I 4d−1 ionization threshold. The resonances include Rydberg series converging to five spin–orbit ligand-field split (I 4d−1) thresholds, as well corresponding excitation from 4d5/2,3/2 orbitals into σ* lowest unoccupied orbital. This study focuses participator that populates lying CH3I+,...
The methylidyne cation (CH$^+$) and the methyl (CH$_3^+$) are building blocks of organic molecules, yet their coupled formation excitation mechanisms remain mainly unprobed. James Webb Space Telescope (JWST), with its high spatial resolution good spectral resolution, provides unique access to detection these molecules. Our goal is use first CH$^+$ CH$_3^+$ rovibrational emission in Orion Bar protoplanetary disk d203-506, irradiated by Trapezium cluster, probe constrain physico-chemical...
Infrared and electronic spectra are indispensable for understanding the structural energetic properties of charged molecules clusters in gas phase. However, presence isomers can potentially complicate interpretation spectra, even if target or mass-selected beforehand. Here, we describe an instrument spectroscopically characterizing molecular that have been selected according to both their isomeric form mass-to-charge ratio. Cluster ions generated by laser ablation a solid sample collision...
The norbornadiene (NBD) molecule, C
Photoelectron velocity map imaging is combined with one- and two-photon ionization to study the near threshold photoionization of 2-butyne molecule. In this region, photoabsorption cross sections display a very intense broad feature that assigned an ℓ = 4, πg shape resonance. The effect resonance on vibrational branching ratios photoelectron angular distributions explored. Theoretical calculations section are in good agreement experiments. results for compared those acetylene, propyne,...
Electronic spectra are measured for mass-selected C2n+(n = 6-14) clusters over the visible and near-infrared spectral range through resonance enhanced photodissociation of tagged with N2 molecules in a cryogenic ion trap. The carbon cluster cations generated laser ablation graphite disk can be selected according to their collision cross section He buffer gas mass prior being trapped spectroscopically probed. data suggest that have monocyclic structures bicyclic becoming more prevalent C22+...
The photoionization and pulsed-field-ionization zero-kinetic-energy photoelectron spectra of the propargyl radical have been recorded in vicinity origin \documentclass[12pt]{minimal}\begin{document}$\tilde{\mathrm{X}}^+\; ^1\mathrm{A}_1 \leftarrow \tilde{\mathrm{X}}\; ^2\mathrm{B}_1$\end{document}X̃+A11←X̃B12 photoionizing transition. An internally cold sample with a rotational temperature ∼45 K was produced supersonic expansion 1,3-butadiene helium. Propargyl generated by excimer laser...
Molecular photoswitches based on the norbornadiene–quadricylane (NBD–QC) couple have been proposed as key elements of molecular solar thermal energy storage schemes. To characterize intrinsic properties such systems, reversible isomerization a charge-tagged NBD–QC carboxylate is investigated in tandem ion mobility mass spectrometer, using light to induce intramolecular [2 + 2] cycloaddition NBD form QC and driving back reaction with collisions. The photoisomerization action spectrum recorded...
Context. Polycyclic aromatic hydrocarbons (PAHs) are believed to be the carriers of infrared bands and have been proposed as candidates explain other astronomical phenomena such diffuse interstellar (DIBs). The first structures possessing more than one ring, 1- 2-cyanonaphthalene (CNN), were recently detected by rotational spectroscopy in dense molecular cloud TMC-1. Laboratory investigations indicated that due fast efficient relaxation through recurrent fluorescence (RF), CNN + may...
Context. The recent detection in pre-stellar sources of cyano-substituted and pure hydrocarbon cycles has emphasized the importance aromatic chemistry earliest stages star formation. Ultraviolet (UV) vacuum-UV (VUV) radiation is ubiquitous space thus photo-processing small cyclic ions may open a window onto rich chemical networks lead to formation larger aromatics space. Aims. aim investigate fate protonated benzonitrile species after UV VUV photoexcitation subsequent potential impact on...
The pulsed-field-ionization zero-kinetic-energy photoelectron spectrum of C2H6 has been recorded in the region adiabatic ionization threshold. partially rotationally resolved indicates existence several vibronic states C2H6+ with less than 600 cm-1 internal excitation. analysis rotational structures assisted by ab initio calculations enabled determination energy and investigation structure dynamics at low energies. ground state is found to be a 2Ag diborane-like strongly mixed (a1g)-1 (eg)-1...
The absolute photoabsorption cross section of propyne was recorded between 62,000 and 88,000 cm(-1) by using the vacuum-ultraviolet, Fourier-transform spectrometer at Synchrotron Soleil. This spans region including lowest Rydberg bands extends above Franck-Condon envelope for ionization to ground electronic state cation, X̃(+). Room-temperature spectra were in a flowing cell 0.9 resolution, jet-cooled 1.8 resolution rotational temperature ~100 K. reduced widths band envelopes latter reveal...
We present new high-resolution data on the photoionization of 2-butyn-1-yl radical (CH3C≡C-•CH2) formed by H atom abstraction from 2-butyne F atoms. The spectra were recorded 7.7 to 11 eV using double-imaging, photoelectron-photoion coincidence spectroscopy, which allows unambiguous correlation photoelectron and mass species. spectrum shows significant resonant autoionizing structure converging excited states C4H5+ cation, similar what is observed in closely related propargyl (HC≡C-•CH2)....
Structural rearrangements in ions are essential for understanding the composition and evolution of energetic chemically active environments. This study explores interconversion routes simple polycyclic aromatic hydrocarbons, namely naphthalene azulene radical cations (C10 H8 + ), by combining mass spectrometry vacuum ultraviolet tunable synchrotron radiation through chemical monitoring technique. Products ion-molecule reactions used to probe C10 structures that formed as a function their...
Rotationally resolved photoelectron spectra of jet-cooled H2O, HDO and D2O have been recorded near the origin photoionising transition following single-photon ionization using complementary techniques mass-analysed threshold-ionization (MATI) pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) spectroscopy. A gas mixture with Ar was obtained by mixing H2O (ℓ) in a reservoir bubbling through mixture. To unambiguously assign bands to or D2O, PFI-ZEKE were compared MATI H2O. Analysis...
The room-temperature photoabsorption spectra of a number linear alkynes with internal triple bonds (e.g., 2-butyne, 2-pentyne, and 2- 3-hexyne) show similar resonances just above the lowest ionization threshold neutral molecules. These features result in substantial enhancement cross sections relative to terminal propyne, 1-butyne, 1-pentyne, ...). Based on earlier work 2-butyne [Xu et al., J. Chem. Phys. 2012, 136, 154303], these are assigned excitation from highest occupied molecular...
(3 + 1) resonantly enhanced multiphoton ionization (REMPI) spectroscopy coupled to photoelectron (REMPI-PES) has been carried out study the Rydberg states of HC3N in 77,000–90,000 cm−1 region. Ab initio calculations (energies and optimized equilibrium geometries) have performed for first time low-lying 2Π, Ã2Σ+ 2Π cation HC3N+ order help analysis. Thanks combination three-photon REMPI spectra, one-photon spectrum unambiguous assignments series their vibrationally excited members are...
The absolute photoabsorption cross sections of 1- and 2-butyne have been recorded at high resolution by using the vacuum-ultraviolet Fourier-Transform spectrometer SOLEIL Synchrotron. Both spectra show more resolved structure than previously observed, especially in case 2-butyne. In this work, we assess potential importance Rydberg states with higher values orbital angular momentum, l, are typically observed experiments from ground state molecules. We how character highest occupied molecular...