A5046160345- Advanced Chemical Physics Studies
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Atmospheric chemistry and aerosols
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Molecular Spectroscopy and Structure
- Spectroscopy and Quantum Chemical Studies
- Inorganic Fluorides and Related Compounds
- Catalysis and Oxidation Reactions
- Photoreceptor and optogenetics research
- Advanced Fluorescence Microscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Photochemistry and Electron Transfer Studies
- Astrophysics and Star Formation Studies
- Photosynthetic Processes and Mechanisms
- Astro and Planetary Science
- Advanced Combustion Engine Technologies
- Laser Design and Applications
- Molecular Junctions and Nanostructures
- Electron Spin Resonance Studies
- Synthesis and Properties of Aromatic Compounds
- Photocathodes and Microchannel Plates
- Atmospheric and Environmental Gas Dynamics
- Ion-surface interactions and analysis
Institut des Sciences Moléculaires d'Orsay
2016-2025
Université Paris-Saclay
2016-2025
Centre National de la Recherche Scientifique
2015-2025
Université Paris-Sud
2010-2020
Centre Hospitalier d'Orsay
2018-2020
Laboratoire de Chimie Physique
2010
Universidade Federal Fluminense
2001-2010
University of Würzburg
2010
Université Libre de Bruxelles
2009
Université Paris Cité
2001-2007
Threshold photoelectron spectra (TPES) of the isotopomers methyl radical (CH3, CH2D, CHD2, and CD3) have been recorded in 9.5−10.5 eV VUV photon energy range using third generation synchrotron radiation to investigate vibrational spectroscopy corresponding cations at a 7−11 meV resolution. A threshold photoelectron−photoion coincidence (TPEPICO) spectrometer based on velocity map imaging Wiley−McLaren time-of-flight has used simultaneously record TPES several species produced Ar-seeded beam...
Methane photolysis has been performed at the two Vacuum UltraViolet (VUV) wavelengths, 121.6 nm and 118.2 nm, via a spectrally pure laser pump-probe technique. The first photon is used to dissociate methane (either or nm) second one ionise CH(2) CH(3) fragments. radical products, CH(3)(X), CH(2)(X), CH(2)(a) C((1)D), have selectively probed by mass spectrometry. In order quantify fragment quantum yields from spectra, photoionisation cross sections carefully evaluated for radicals, in steps:...
To better understand the photophysics of photoactive proteins, absorption bands several gas-phase biomolecules have been studied recently at electrostatic heavy-ion storage ring ELISA by a photo-fragmentation technique. In present paper we discuss involved and photochemistry for protonated deprotonated model chromophores Green Fluorescent Protein (GFP) Red (RFP). We show specifically that delayed dissociation after photoabsorption can be understood in terms thermally activated process...
A pyrolysis source coupled to a supersonic expansion has been used produce the CH3 radical from two precursors, iodomethane CH3I and nitromethane CH3NO2. The relative ionization yield of recorded at SOLEIL Synchrotron Radiation in range 9.0-11.6 eV, its threshold modeled by taking into account vibrational rotational temperature molecular beam. photoionization normalized an absolute cross section scale fixed wavelength (118.2 nm, sigma(i)(CH3) = 6.7(-1.8)(+2.4) Mb, 95% confidence interval)...
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...
The absolute photoionization cross section of C2H5 has been measured at 10.54 eV using vacuum ultraviolet (VUV) laser photoionization. radical was produced in situ the rapid C2H6 + F → HF reaction. Its determined two different ways: first NO2 C2H5O NO reaction a fast flow reactor, and known NO. In second experiment, it relative to CH3 as reference by CH4 reactions successively. Both methods gave similar results, one being more precise yielding value: σC2H5ion = (5.6 ± 1.4) Mb eV. This value...
The threshold-photoelectron spectrum of silylene (SiH 2 ) has been successfully recorded using synchrotron radiation in the range 8–11 eV.
Silicon monosulfide (SiS) is an important molecule in astrochemistry likely linked to dust production through the formation of sulfide particles. This work presents vacuum ultraviolet photoionisation SiS formed situ a discharge flow reactor, particular threshold photoelectron spectrum covering first three electronic states SiS+ cation. The rich vibronic structure assigned with support ab initio calculations and spin orbit coupling constant -323 ± 41 cm-1 measured for ground state. Adiabatic...
Reactive intermediates such as aryl cations play crucial roles in organic and astrochemical processes, yet their characterization remains a significant experimental challenge. The present study offers the first partially vibrationally resolved photoelectron spectrum of phenyl radical (C6H5), focusing on ionization thresholds to lowest singlet triplet states its cation. Using synchrotron-based spectroscopy, we directly determine adiabatic energy state phenylium (C6H5+, IEad(ã+ ← X̃) =...
The study employs threshold photoelectron spectroscopy (TPES) using vacuum ultraviolet synchrotron radiation to refine spectroscopic constants and fundamental energies of monosulfur monofluoride (SF). High‐precision adiabatic ionization energy (AIE) measurements were achieved, that could serve as benchmarks for future calculation enthalpy formation SF its ionized form, SF+. Experimental methods utilized include a microwave discharge reactor coupled with synchrotron‐based spectroscopy,...
Abstract The resonance-stabilization of the propargyl radical (C 3 H ) makes it among most important reactive intermediates in extreme environments and grants a long enough lifetime to recombine both terrestrial combustion media cold molecular clouds space. This self-reaction pivotal step formation benzene, first aromatic ring, eventually lead polycyclic hydrocarbons variety environments. In this work, by producing radicals flow tube where propyne reacted with F atoms probing reaction...
Photoabsorption studies of red fluorescent protein chromophore anions have been performed at the ELISA electrostatic heavy-ion storage ring. The broad absorption band due to electronic excitation chromophores is tuned a longer wavelength (redshifted) by extending conjugation molecule. A clear vibrational progression resolved with E(vib) approximately 380 and 520 cm(-1) for two different forms chromophore. modes correspond collective motions entire molecular structure. It argued that excited...
The planar isomerization routes of the vinylidene/acetylene cation in lowest electronic states are accurately examined for first time, by using large scale MRCI and CCSDT calculations a complementary way. They compared with similar performed neutral ground state isomerization. An accurate value adiabatic ionization potential vinylidene (11.26 eV) is predicted. state, 1 2A1, follows an almost flat pathway shallow secondary minimum on 2A' energy surface, before suddenly dropping to stable...
UV laser excitation of cryogenic solids doped with cyanoethyne, HC3N, led to an in situ creation longer carbon–nitrogen chains, namely HC5N, C4N2, and C6N2, heralded by their strong visible luminescence. HC5N C4N2 molecules can form, most probably, within HC3N aggregates linked hydrogen bonds, while the reaction occurring between two isolated, photochemically created C3N radicals yields C6N2. This latter species, dicyanobutadiyne, is easily detected Ar, Kr, N2, as well parahydrogen solids....
The absorption spectra of two compounds, RFP(1) and RFP(2), designed to model the chromophore Red Fluorescent Protein DsRed have been recorded in gas phase with a heavy-ion storage ring technique. Both anions cations were investigated. electronic delocalization is greater RFP(2) than due an additional CC double bond conjugation π system, bands are red-shifted compared those RFP(1). Band maxima 549 nm 521 nm, respectively, 448 441 respectively. These values good agreement calculated HOMO–LUMO...
Photolysis of acetylene has been performed by vacuum-ultraviolet excitation with the synchrotron radiation via Rydberg states converging to first ionization potential (IP) at 11.4 eV. Only visible fluorescence ethynyl radical was observed in à 2Π–X̃ 2Σ+ system. Excitation several over a large energy range between 9 and eV allowed us observe for time evolution this continuum increasing excitation. Intensity calculations based on accurate ab initio surfaces C2H were using one-dimensional model...
The A-X bands of the CH radical, produced in a 248 nm two-photon photolysis or supersonic jet discharge CHBr(3), have been observed via cavity ring-down absorption spectroscopy. Bromoform is well-known photolytic source radicals, though no quantitative measurement production efficiency has yet reported. aim present work to quantify from both and CHBr(3). In case photolysis, range pressure laser fluences was carefully chosen avoid postphotolysis reactions with highly reactive radical. at...
A quantitative characterization of the Rydberg and valence singlet electronic states acetylene lying in 5−10.7 eV region is performed by using large-scale ab initio calculations. special attention paid on comparison between present calculations Mulliken's concepts for states, based single-electron single-configuration description. Most properties have been qualitatively understood via this comparison, mainly shown shape size outer molecular orbital. More quantitatively, Rydberg−valence...
The cyano radical is a ubiquitous molecule and was, for instance, one of the first species detected in astrophysical media such as comets or diffuse clouds. In photodissociation regions, reaction rate CN+ + CO → CN CO+ critical parameters defining nitrile chemistry. enthalpy this charge transfer defined difference ionization energies (EI) between CO. Although EI(CO) known accurately, EI(CN) values are more dispersed deduced indirectly from thermodynamic thresholds only, all above EI(CO),...
The gas-phase absorption properties of a blue GFP-mutant chromophore have been investigated in an electrostatic heavy-ion storage ring combined with electrospray ion source. From the production neutral photofragments, profiles both protonated and deprotonated forms obtained compared their homologues liquid phase protein. Maximum for anion is found around 456 nm solution gas phase. It matches one maximum W7 protein, which suggests that this due to anionic form chromophore—similar case GFP....
The 193nm laser irradiation of cyanoacetylene (HCCCN) that was isolated in rare gas solids led to a long-lived luminescence (origin at 3.58eV), which assigned the ãΣ+3-X̃Σ+1 system cyanoacetylide (CCCN−). identification, involved N15 and H2 isotopic substitution studies, is based on vibronic spacings phosphorescence spectrum (compared previous infrared absorption measurements theoretical results regarding CCCN− vibrational frequencies), as well BD(T)/cc-pVTZ prediction for singlet-triplet...
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...