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Introduction
Additional affiliations
October 1995 - present
October 1995 - present
November 1994 - November 1995
Education
June 2009
November 1994 - September 1995
Laboratoire de Spectroscopie d'Electrons Diffusés
Field of study
- Theoretical K-shell spectroscopy
October 1991 - October 1994
Publications
Publications (108)
We present the detailed topographical characterisation (stationary points and minimum energy paths connecting them) of the full dimensional (81D) intermolecular potential energy surface associated with the non‐covalent interactions between the NO2 radical and the pyrene (C16H10) molecule. The whole procedure is (quasi) fully automated. We have used...
Ice clouds in the upper troposphere are crucial for regulating Earth’s climate by affecting stratospheric humidity and the global radiative balance. A key aspect of cloud formation is heterogeneous ice...
Although UV photon-induced CO ice desorption is clearly observed in many cold regions of the Universe as well as in the laboratory, the fundamental question of the mechanisms involved at the molecular scale remains debated. In particular, the exact nature of the involved energy transfers in the indirect desorption pathway highlighted in previous ex...
The electronic state spectroscopy of 2(5H)-thiophenone, C 4 H 4 OS, has been investigated by high-resolution vacuum ultraviolet photoabsorption in the 3.76–10.69 eV energy range using synchrotron radiation, together with novel quantum chemical calculations performed at the equation of motion coupled cluster singles and doubles (EOM-CCSD) level of t...
The interstellar medium (ISM) is the site of a rich chemistry that evolves from simple to complex organic molecules. To date, a large number of molecular species (more than 220) have been detected in the ISM. The formation and decomposition routes of the different species must be quantitatively understood in order to interpret the observed spectra...
Formaldehyde has been widely observed in the icy mantle of interstellar grains. H2CO may be formed from successive hydrogenations of CO and may further contribute to the chemical complexity of the Interstellar medium (ISM) participating to heterogeneous reactions with colliding gas phase atoms. Within this context, Eley-Rideal and Langmuir-Hinshelw...
We investigate for the first time the gas-phase lowest-lying valence, Rydberg and ionic electronic states of 2,4,6-trichloroanisole (TCA) using synchrotron radiation for photoabsorption and photoelectron spectroscopy. The high-resolution vacuum ultraviolet photoabsorption spectrum, in the 4.0–10.8 eV energy-range, has been measured with absolute ph...
The adsorption of a series of atoms and small molecules and radicals (H, C, N, O, NH, OH, H 2 O, CH 3 , and NH 3 ) on hexagonal crystalline and amorphous ice clusters were obtained via classical molecular dynamics and electronic structure methods. The geometry and binding energies were calculated using a QMHigh:QMLow hybrid method on model clusters...
We investigate the methanol absorption spectrum in the range 5.5-10.8 eV in order to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol's electronic state spectroscopy by employing high-resolution vacuum ultraviolet (VUV) photoabsorption measurements together with stat...
We present novel results of the analysis of the electronic structure of two aliphatic esters: methyl butyrate and methyl valerate. High-resolution photoabsorption spectra were collected and analyzed over the energy range 4.0–10.8 eV and showed for both the molecules not only a clear band of the HOMO to LUMO transition, but also vibronic structure a...
We present a comprehensive revisited experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of ammonia, NH3, covering for the first time the full 5.4–10.8 eV energy-range, with absolute cross sections determined. The calculations on the vertical excitation energies and oscillator strengths were performed using the equation-o...
The emission and use of synchrotron radiation (SR) are powerful tools for performing state-of-the art research at the fundamental and applied levels, benefiting a diversity of research areas across medicine, molecular and cell biology, condensed matter physics, nanotechnology, cultural heritage, environmental science, atomic and molecular physics,...
The growth of small valeric and glutaric acid aerosol particles from 20 to 500 molecules has been studied at room temperature using classical molecular dynamics simulations. Due to a higher propensity to form hydrogen bonds, glutaric acids aggregates are shown to be denser than their valeric counterpart. Addition of water molecules with water: acid...
Photoabsorption spectra of isoflurane and sevoflurane have been measured with synchrotron radiation over the photon range 5.0–10.8 eV. Low-lying excited singlet valence and Rydberg states are investigated and the assignments supported by quantum chemical calculations, the latter also helping to identify the triplet states. This provides the first c...
Perfluorocarbons is a class of fully fluorinated compound, highly persistent and toxic pollutants that are receiving increasing attention due to their widespread environmental distribution. In this study, the attention was focused on one compound in particular, the perfluorooctanoic acid (PFOA). We report the first investigation on the UV‐VUV photo...
Carotenoids are important natural pigments and micronutrients contributing to health prevention by several mechanisms, including their electron-donating (antioxidant) activity. In this work, a large series of carotenoids, including 11 carotenes and 14 xanthophylls, has been investigated by wavelength-resolved atmospheric pressure photoionization ma...
Electron energy loss spectra of carbon tetrafluoride, silicon tetrafluoride, and germanium tetrafluoride molecules (CF4, SiF4, and GeF4) have been measured for incident electron energies of 50–360 eV at 1.5°–15.5° and for 30 eV and 30° scattering angle, while sweeping the energy loss over the range 9.0–20.0 eV. Low-lying valence excited triplet and...
Models of atmospheric chemistry are widely used to perform projections of future changes in the chemical composition of the global troposphere, including changes in climate related to greenhouse gases and aerosol particles. However, large uncertainties are still associated with the chemistry implemented in these models (Boucher 2013), which in turn...
Photoionization of a buckminsterfullerene ion is investigated using an ion trap and a merged beam setup coupled to synchrotron radiation beamlines and compared to theoretical calculations. Absolute measurements derived from the ion trap experiment allow discrepancies concerning the photoionization cross section of C-60(+) to be solved.
Marine aerosols represent the most important aerosol fraction in the Earth atmosphere. Field studies have revealed that fatty acids form an organic film at the surface of sea salt particles, altering the properties of the aerosol. By means of classical molecular dynamics simulation, the surface organization of Palmitic Acid (PA) on a salt surface,...
Electron energy loss (EEL) spectra of GeF4 have been measured with incident electrons at 100 eV for 5° scattering angle and at 30 eV for 30° scattering angle, while sweeping the energy loss over the range 7.0−21.0 eV. Low-lying excited triplet, singlet, valence and Rydberg states are investigated and the assignments supported by quantum chemical ab...
Because of the very peculiar conditions of chemistry in many astrophysical gases (low densities, mostly low temperatures, kinetics-dominated chemical evolution), great efforts have been devoted to study molecular signatures and chemical evolution. While experiments are being performed in many laboratories, it appears that the efforts directed towar...
We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3–10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional th...
In the nitrosyl halides series (XNO, where X = F, Cl, Br, I), INO is the only chemical species whose rotational spectrum has not been reported. Nitrosyl iodide, together with the nitryl (INO2), nitrite (IONO) and nitrate (IONO2) iodides, are believed to impact tropospheric ozone levels. Guided by our quantum chemical calculations, we report the det...
The electronic spectroscopy of isolated toluene in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 4.0-10.8 eV energy-range, with absolute cross-section measurements derived. We present the first set of ab initio calculations (vertical energies and oscillator strengths), which we use in the assignment o...
We present the first set of ab initio calculations (vertical energies and oscillator strengths) of the valence and Rydberg transitions of the anaesthetic compound halothane (CF3CHBrCl), These results are complemented by high resolution vacuum ultraviolet (VUV) photoabsorption measurements over the wavelength range 115-310 nm (10.8-4.0 eV). The spec...
The chlorine/water interface is of crucial importance in the context of atmospheric chemistry. Modeling the structure and dynamics at this interface requires an accurate description of the interaction potential energy surfaces. We propose here an analytical intermolecular potential that reproduces the interaction between the Cl2 molecule and a wate...
Models of atmospheric chemistry are widely used to perform projections of future changes in the chemical composition of the global troposphere, including changes in climate related greenhouse gases and aerosol particles. However, large uncertainties are still associated with the chemistry implemented in these models, which in turn can lead to inacc...
Bromoiodomethane, CH2BrI, is a molecule of natural origin emitted in significant amount into the marine boundary layer. It can easily be decomposed by solar radiation, releasing Br and I atoms in the troposphere, which in turn impacts the atmospheric chemistry. Spectroscopy is an invaluable tool to monitor species present in the atmosphere. Since n...
In this contribution we probe BF3 low-lying excited singlet states measured at 100 eV, 2.8° scattering angle and triplet states at 40 eV, 40° scattering angle, while sweeping the energy loss over the range 10.0-20.0 eV. The electronic state spectroscopy has been investigated and the assignments supported by quantum chemical calculations. This provi...
The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO,
yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing
several new spectral features. Valence and Rydberg transitions and their associated vibronic
series, observed in the photoabsorption spectrum, have been assigned i...
We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20-50 eV, while the scattered electron was detected in the 10°-90° angular range. There are currently no other experimental data or...
We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol. The energy range of these experiments was 20–50 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our indep...
We report on the measurements of the electron impact electronic excitation cross sections for XF4 (X =
C, Si and Ge) molecules at 100 eV, 5o scattering angle and 30 eV, 30o in the electron energy loss range 8.0 – 18
eV. For a target of GeF4 molecule, the optically-forbidden behavior has been observed in the lower electron energy loss range.
The electronic spectroscopy of isolated tetrahydrofurfuryl alcohol (THFA) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 5.0-10.8 eV energy-range, with absolute cross-section measurements derived. The He(I) photoelectron spectrum was also collected to quantify ionisation energies in the 9-16 eV spec...
We report the first global potential energy surface (PES) for the X( 2)A(') ground electronic state of the Si((3)P) + OH(X(2)Π) → SiO(X(1)Σg (+)) + H((2)S) reaction. The PES is based on a large number of ab initio energies obtained from multireference configuration interaction calculations plus Davidson correction (MRCI+Q) using basis sets of quadr...
Context. Millimetric observations have measured high degrees of molecular
deuteration in several species seen around low-mass protostars. The Herschel
Space Telescope, launched in 2009, is now providing new measures of the
deuterium fractionation of water, the main constituent of interstellar ices.
Aims. We aim at theoretically studying the formati...
The title reaction has been calculated using complete active space self-consistent field and internally contracted multi-reference configuration interaction, including Davidson correction, calculations. Dunning's correlation consistent atomic basis sets, together with several complete basis set extrapolation schemes, were employed. Core-valence and...
A valence shell study of electrosprayed insulin protein polyanion photodetachment was carried out on a vacuum ultra-violet synchrotron radiation beamline coupled to a radiofrequency ion trap, for both close- and open-shell species. A two-electron photodetachment is observed, which arises from two different mechanisms that are disentangled: a sequen...
This Letter reports on the first measurements of the lowest lying triplet states as studied by electron energy loss spectroscopy for C4F6 isomers, hexafluoro-1,3-butadiene (1,3-C4F6), hexafluorocyclobutene (c-C4F6) and hexafluoro-2-butyne (2-C4F6). This study has been performed at an incident electron energy of 30 eV, 30°, whilst sweeping the energ...
We have measured electronic excitation differential cross sections for C 4 F 6 molecules isomers by electron impact. In the case of hexafluoro-1,3-butadiene we observed an optical forbidden transition at around 5 eV. The spectra of the three C 4 F 6 isomers show the most intense band clearly shifted to lower energies when going from 2-C 4 F 6 , to...
We report on the first measurements of the electron impact electronic excitation cross sections for C(4)F(6) isomers, hexafluoro-1,3-butadiene (1,3-C(4)F(6)), hexafluorocyclobutene (c-C(4)F(6)), and hexafluoro-2-butyne (2-C(4)F(6)), measured at 100 eV, 3° scattering angle, while sweeping the energy loss over the range 2.0-15.0 eV. Under these exper...
We present high resolution VUV photoabsorption spectra of 1,4-pentadiene, C(5)H(8), over the wavelength range 115-247 nm (10.8-5.0 eV). These spectra reveal several new features not previously reported in the literature. These measurements are complemented by the first ab initio calculations for the three most abundant conformational isomers of 1,4...
The vibrational structure of the K-shell O1s → π∗ of acenaphthenequinone C(12)H(6)O(2) and its halogenated compound C(12)H(2)Br(2)Cl(2)O(2) has been simulated using an entirely ab initio approach. For both molecules, analysis of the calculated Franck-Condon factors confirm without ambiguity that, contrary to initial claims, the C-H stretching modes...
Electronic state spectroscopy of limonene has been investigated using vacuum ultraviolet photoabsorption spectroscopy in the energy range 5.0-10.8 eV. The availability of a high resolution photon beam (~0.075 nm) enabled detailed analysis of the vibrational progressions and allowed us to propose, for the first time, new assignments for several Rydb...
Guided by a previous microwave study (9–35 GHz), the rotational spectrum of both chlorine isotopo-logues of chloroiodomethane in its vibrational and electronic ground state has been re-investigated in the microwave region and extended to the millimeter/submillimeter-wave region. Weaka-type transi-tions have been recorded by Fourier transform microw...
A concerted hydrogen atom transfer mechanism has been elucidated for the isomerization of trans-HCOH to H(2)CO using a variety of ab initio and density functional theory methods. This work places specific emphasis on the role water molecules can play as a catalyst for this reaction and the mechanism by which this is achieved. This is of particular...
This paper reports on the first measurements of the electron impact electronic excitation cross-sections for carbonyl fluoride, F(2)CO, measured at 30 eV, 10° and 100 eV, 5° scattering angle, while sweeping the energy loss over the range 5.0-18.0 eV. The electronic-state spectroscopy has been investigated and the assignments are supported by quantu...
The first ab initio calculations of the vertical excitation energies and oscillator strengths are presented for the neutral electronic transitions of methyl formate, C(2)H(4)O(2). The highest resolution VUV photoabsorption spectrum of the molecule yet reported is presented over the wavelength range 115 to 310 nm (10.8 to 4.0 eV) revealing several n...
A concerted hydrogen atom transfer mechanism has been derived for the isomerization of trans-HCOH to H2CO. This mechanism has been elucidated by using a variety of ab initioand DFT methods. This work places specific emphasis on the role that water can play as a catalyst for this reaction and the mechanism by which this is achieved. This is of parti...
Ab initio calculations have been carried out in order to assign the bands observed in the carbon and oxygen K-shell spectra of gaseous tetrahydrofuran (THF), measured using inner-shell electron energy loss spectroscopy (ISEELS). The good agreement between the theoretical and the measured spectra allows us to re-assign precisely most of the peaks. T...
The first ab initio calculations (vertical energies and oscillator strengths) are reported for the neutral electronic transitions of isoprene (2-methyl-1,3-butadiene), CH(2)CHC(CH(3))CH(2). The VUV photoabsorption spectroscopy of the molecule is presented in the energy range 4.6 to 10.8 eV (270-125 nm) with the highest resolution yet reported above...
We present a detailed study of the potential energy surfaces (PES) of the semi-heavy water dication HOD2+ correlating asymptotically with O(3P) and O(1D). Using multi reference configuration interaction method, we generated a large set of data, which was used to fit the ground state and the first 7 excited PES for bending angles theta >= 80o and OH...
We present a detailed study of the potential energy surfaces of the water dication correlating asymptotically with O((3)P) and O((1)D). Using ab initio multireference configuration interaction method, we computed a large ensemble of data, which was used to generate a fit of each potential energy surface for bending angles theta > or = 80 degrees de...
Absolute photoabsorption cross sections of propionic (C2H5COOH), butyric (C3H7COOH), and valeric (C4H9COOH) acids have been measured from the dissociative pi* <-- n(o) transition (beginning around 5.0 eV) up to 10.7 eV. This constitutes the first study of the neutral electronic states of propionic and butyric acids at energies above the pi* <-- n(o...
Ce travail présente une synthèse des activités de recherche effectuées pendant mon stage post-doctoral à l'Université de Liège (Belgique) et depuis ma nomination en tant que Maître de Conférences à l'Université Lille1. La thèmatique générale est l'application des méthodes de la chimie quantique, essentiellement les techniques d'interactions de conf...
The electronic spectroscopy of isolated tetrahydrofuran (THF) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 5.8–10.6 eV with absolute cross-section measurements derived. In addition, an electron energy loss spectrum was recorded at 100 eV and 10° over the 5–11.4 eV range. The He(I) photoelectron sp...