Peer-reviewed Publications |
Arabei, S. M., Galaup, J. - P., McCaffrey, J. G., Shafizadeh, N., & Crepin, C. (2012). Electronic spectroscopy, stimulated emission, and persistent spectral hole burning of cryogenic nitrogen matrices doped with tetrabenzoporphin. LOW TEMPERATURE PHYSICS, 38(8), 727–731.
Résumé: This paper deals with our on-going work on the electronic spectroscopy of tetrapyrrole molecules embedded in cryogenic hosts. Under nanosecond laser excitation of free-base tetrabenzoporphin molecules in a nitrogen matrix at 8 K, increasing laser pulse energy results in essential enhancement of the intensity of one or several vibronic emission lines in the fine-structure fluorescence spectrum. Some characteristics of stimulated radiation are realized in the observed intense monochromatic: radiation as a result of a transition from the purely electronic S-1 level to a vibrational sublevel of the S-0 state, corresponding to the excitation of C-C stretching vibrations of tetrapyrrole methane bridges. We also report on persistent spectral hole-burning effects. Hole and antihole formation analysis gives some insight on the photochemical properties of tetrabenzoporphin in a nitrogen matrix. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4746794]
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Bailleux, S., Martin-Drumel, M. A., Margules, L., Pirali, O., Wlodarczak, G., Roy, P., Roueff, E., Gerin, M., Faure, A., & Hily-Blant, P. (2012). High-resolution terahertz spectroscopy of the (NH)-N-15 radical ((X)over-tilde (3)Sigma(-)). ASTRONOMY & ASTROPHYSICS, 538, A135.
Résumé: Context. High-resolution rotational spectroscopy of the imidogen radical has been limited to the (NH)-N-14 and (ND)-N-14 isotopologues. Imidogen is an important intermediate in the astronomical synthesis of ammonia. Recently, the N-14/N-15 isotopic ratio in ammonia has been obtained in cold, dense molecular clouds. Aims. We conducted a laboratory search for rotational transitions of (NH)-N-15 to investigate in more detail the N-14/N-15 ratio in the interstellar medium. Methods. (NH)-N-15 was generated in a positive column discharge in a flowing (NH3)-N-15 – He (SOLEIL synchrotron) or (NH3)-N-15 – Ar (PhLAM) mixture. High-resolution spectroscopic study of the (NH)-N-15 isotopologue of imidogen in its ground electronic and vibrational state ((X) over tilde (3)Sigma(-)) was carried out in the THz range (up to 225 cm(-1)) with the AILES beamline of the SOLEIL synchrotron and subsequently with the PhLAM spectrometer (around 942 GHz). The observed fine and hyperfine structures were analysed, yielding an accurate set of rotational, fine, and hyperfine parameters. Results. The reported frequencies and molecular constants are suitable for radioastronomical searches of this key species and for N-14/N-15 isotopic ratio astronomical determination.
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Calvo, F., & Parneix, P. (2012). Amplification of Anharmonicities in Multiphoton Vibrational Action Spectra. CHEMPHYSCHEM, 13(1), 212–220.
Résumé: The influence of one or several infrared laser pulses on the stability of bare and argon-tagged sodium chloride clusters is investigated theoretically by a combination of computational methods involving explicit molecular dynamics and properly calibrated unimolecular rate theories. The fragmentation spectra obtained by varying the laser frequency in the far-IR range is compared to the linear absorption spectrum resulting from the dipole moment autocorrelation function. Under appropriate laser field parameters, the action spectra are found to resemble the absorption spectra quite accurately in terms of positions, line widths, and even relative intensities. However, the action spectra exhibit residual and systematic redshifts of a few percent, which are partly due to the finite spectral bandwidth but are amplified by the progressive heating by the laser. A quantitative analysis suggests that these anharmonicity effects should generally arise upon multiple photon absorption.
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Calvo, F., & Parneix, P. (2012). Multiscale modeling of vibrational predissociation spectra under a chirped laser pulse. EUROPEAN PHYSICAL JOURNAL D, 66(6), 165.
Résumé: The vibrational predissociation spectrum of the argon-tagged ionic cluster (NaCl)(32) due to exposure to a chirped infrared laser was theoretically calculated in a time multiscale framework. The response to the laser field is modeled explicitly by molecular dynamics simulations, and statistical rate theories are used to evaluate the long-time dissociation probability. Due to anharmonicities and multiphoton processes, the predissociation spectrum shows some small but systematic red shift in the main absorption line. Negative chirping toward lower frequencies further enhances this effect, and also alters the band intensity and the band width. Positive chirping attenuates the dissociation efficiency.
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Calvo, F., Nguyen-Thi Van-Oanh, Parneix, P., & Falvo, C. (2012). Vibrational spectra of polyatomic molecules assisted by quantum thermal baths. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 14(30), 10503–10506.
Résumé: We assess the performance of colored-noise thermostats to generate quantum mechanical initial conditions for molecular dynamics simulations, in the context of infrared spectra of large polyatomic molecules. Comparison with centroid molecular dynamics simulations taken as reference shows that the method is accurate in predicting line shifts and band widths in the ionic cluster (NaCl) 32 and in the naphthalene molecule. As illustrated on much larger polycyclic aromatic hydrocarbons, the method also allows fundamental spectra to be evaluated in the limit of T = 0, taking into account anharmonicities and vibrational delocalization.
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Carpentier, Y., Feraud, G., Dartois, E., Brunetto, R., Charon, E., Cao, A. T., d'Hendecourt, L., Brechignac, P., Rouzaud, J. N., & Pino, T. (2012). Nanostructuration of carbonaceous dust as seen through the positions of the 6.2 and 7.7 μm AIBs. ASTRONOMY & ASTROPHYSICS, 548, A40.
Résumé: Context. Carbonaceous cosmic dust is observed through infrared spectroscopy either in absorption or in emission. The details of the spectral features are believed to shed some light on its structure and finally enable the study of its life cycle. Aims. The goal is to combine several analytical tools in order to decipher the intimate nanostructure of some soot samples. Such materials provide interesting laboratory analogues of cosmic dust. In particular, spectroscopic and structural characteristics that help to describe the polyaromatic units embedded into the soot, including their size, morphology, and organisation are explored. Methods. Laboratory analogues of the carbonaceous interstellar and circumstellar dust were produced in fuel-rich low-pressure, premixed and flat flames. The soot particles were investigated by infrared absorption spectroscopy in the 2-15 μm spectral region. Raman spectroscopic measurements and high-resolution transmission electron microscopy were performed, which offered complementary information to better delineate the intimate structure of the analogues. Results. These laboratory analogues appeared to be mainly composed of sp(2) carbon, with a low sp(3) carbon content. A cross relation between the positions of the aromatic C=C bands at about 6.2 micron and the band at about 8 micron is shown to trace differences in shapes and structures of the polyaromatic units in the soot. Such effects are due to the defects of the polyaromatic structures in the form of non-hexagonal rings and/or aliphatic bridges. The role of these defects is thus observed through the 6.2 and 7.7 μm aromatic infrared band positions, and a distinction between carriers composed of curved aromatic sheets and more planar ones can be inferred. Based on these nanostructural differences, a scenario of nanograin growth and evolution is proposed.
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Cuisset, A., Pirali, O., & Sadovskii, D. A. (2012). Gyroscopic Destabilization of Molecular Rotation and Quantum Bifurcation Observed in the Structure of the nu(23) Fundamental of Dimethylsulfoxyde. PHYSICAL REVIEW LETTERS, 109(9), 094101.
Résumé: Following the first successful high-resolution study of the “perpendicular” band of dimethylsulfoxyde at 324 cm(-1), associated with the nu(23) bending vibration, we discovered a sequence of fourfold degenerate clusters of rotational levels at high angular momenta J > 40. This unusual system of localized states corresponds to classical rotations about a pair of “tilted” axes, which become stationary at high J, after the principal axis of inertia A loses stability and bifurcates for J approximate to 27.
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Dai, X., Richter, M., Li, H., Bristow, A. D., Falvo, C., Mukamel, S., & Cundiff, S. T. (2012). Two-Dimensional Double-Quantum Spectra Reveal Collective Resonances in an Atomic Vapor. PHYSICAL REVIEW LETTERS, 108(19), 193201.
Résumé: We report the observation of double-quantum coherence signals in a gas of potassium atoms at twice the frequency of the one-quantum coherences. Since a single atom does not have a state at the corresponding energy, this observation must be attributed to a collective resonance involving multiple atoms. These resonances are induced by weak interatomic dipole-dipole interactions, which means that the atoms cannot be treated in isolation, even at a low density of 10(12) cm(-3).
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Falvo, C., Calvo, F., & Parneix, P. (2012). Probing the spin multiplicity of gas-phase polycyclic aromatic hydrocarbons through their infrared emission spectrum: A theoretical study. JOURNAL OF CHEMICAL PHYSICS, 137(6), 064303.
Résumé: The anharmonic infrared emission spectrum following an optical excitation has been calculated for a variety of polycyclic aromatic hydrocarbon molecules in their ground singlet electronic state or in their triplet state. The computational protocol relies on second-order perturbation theory and involves a quartic vibrational Hamiltonian, the vibrational quantum numbers being sampled according to a Monte Carlo procedure. In the case of neutral naphthalene, the IR spectrum obtained in the (ground) singlet state differs significantly from the spectrum in the triplet state, especially for out-of-plane CH bending modes. Although not as prominent, spectral differences in larger molecules are still observable.
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Falvo, C., Zhuang, W., Kim, Y. S., Axelsen, P. H., Hochstrasser, R. M., & Mukamel, S. (2012). Frequency Distribution of the Amide-I Vibration Sorted by Residues in Amyloid Fibrils Revealed by 2D-IR Measurements and Simulations. JOURNAL OF PHYSICAL CHEMISTRY B, 116(10), 3322–3330.
Résumé: The infrared optical response of amyloid fibrils A beta(1-40) is investigated. Simulations of two models corresponding to different protonation states are compared with experiment. The simulations reveal that vibrational frequency distributions inside the fibrils are dominated by side chain fluctuations. We further confirm earlier suggestions based on 2D-IR measurements that water molecules can be trapped inside the fibrils.
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Gamache, R. R., Lamouroux, J., Laraia, A. L., Hartmann, J. - M., & Boulet, C. (2012). Semiclassical calculations of half-widths and line shifts for transitions in the 30012 <- 00001 and 30013 <- 00001 bands of CO2, I: Collisions with N-2. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 113(11), 976–990.
Résumé: Calculations of the half-width, its temperature dependence, and the line shift are made for the rotational states J = 0-120 for two of the Fermi-tetrad bands (30012 <- 00001 and 30013 <- 00001) of CO2 perturbed by N-2. The calculations employ the semi-classical complex Robert-Bonamy method with no ad hoc scaling, J-dependent or otherwise, and an intermolecular potential (IP) comprised of an electrostatic part, an atom-atom part, and an isotropic London dispersion part. The averaging over the impact parameter b and relative speed v are explicitly carried out. Many interesting features about CO2 as the radiating molecule are elucidated. Effects of the trajectory model, the order of the expansion of the atom-atom component of the potential, and the inclusion of the imaginary terms are studied. It is shown that the results are very sensitive to the intermolecular potential. The final IP parameters give results that demonstrate excellent agreement with measurement for the three line shape parameters studied in this work. (C) 2012 Elsevier Ltd. All rights reserved.
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Hartmann, J. - M., & Boulet, C. (2012). Quantum and classical approaches for rotational relaxation and nonresonant laser alignment of linear molecules: A comparison for CO2 gas in the nonadiabatic regime. JOURNAL OF CHEMICAL PHYSICS, 136(18), 184302.
Résumé: A quantum approach and classical molecular dynamics simulations (CMDS) are proposed for the modeling of rotational relaxation and of the nonadiabatic alignment of gaseous linear molecules by a nonresonant laser field under dissipative conditions. They are applied to pure CO2 and compared by looking at state-to-state collisional rates and at the value of < cos(2)[theta(z)(t)]> induced by a 100 fs laser pulse linearly polarized along (z) over right arrow. The main results are: (i) When properly requantized, the classical model leads to very satisfactory predictions of the permanent and transient alignments under non-dissipative conditions. (ii) The CMDS calculations of collisional-broadening coefficients and rotational state-to-state rates are in very good agreement with those of a quantum model based on the energy corrected sudden (ECS) approximation. (iii) Both approaches show a strong propensity of collisions, while they change the rotational energy (i. e., J), to conserve the angular momentum orientation (i. e., M/J). (iv) Under dissipative conditions, CMDS and quantum-ECS calculations lead to very consistent decays with time of the “permanent” and transient components of the laser-induced alignment. This result, expected from (i) and (ii), is obtained only if a properly J- and M-dependent ECS model is used. Indeed, rotational state-to-state rates and the decay of the “permanent” alignment demonstrate, for pure CO2, the limits of a M-independent collisional model proposed previously. Furthermore, computations show that collisions induce a decay of the “permanent” alignment about twice slower than that of the transient revivals amplitudes, a direct consequence of (iii). (v) The analysis of the effects of reorienting and dephasing elastic collisions shows that the latter have a very small influence but that the former play a non-negligible role in the alignment dynamics. (vi) Rotation-translation collisionally induced transfers have also been studied, demonstrating that they only slightly change the alignment dissipation for the considered laser energy conditions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705264]
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Herberth, D., Baum, O., Pirali, O., Roy, P., Thorwirth, S., Yamada, K. M. T., Schlemmer, S., & Giesen, T. F. (2012). Far infrared Fourier-transform spectroscopy of mono-deuterated hydrogen peroxide HOOD. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 113(11), 1127–1133.
Résumé: We present the gas phase spectrum of singly deuterated hydrogen peroxide, HOOD, in its vibrational ground state, recorded by the high resolution Fourier-transform interferometer located at the AILES synchrotron beamline connected to SOLEIL More than 1000 transitions in the range from 20 to 143 cm(-1) were assigned, leading to a set of preliminary rotational and centrifugal distortion constants determined by least squares fit analysis. All transitions are split by the tunneling motion of a hindered internal rotation. The splitting has been determined to be 5.786(13)cm(-1) in the torsional ground state and it shows a dependence on the rotational quantum number K-a. Some perturbations were not treated yet, but the present analysis permits to obtain a preliminary set of parameters. (C) 2012 Elsevier Ltd. All rights reserved.
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Houzet, J., Gateau, J., Hertz, E., Billard, F., Lavorel, B., Hartmann, J. - M., Boulet, C., & Faucher, O. (2012). Probing ultrafast thermalization with field-free molecular alignment. PHYSICAL REVIEW A, 86(3), 033419.
Résumé: The rotation-translation thermalization of CO2 gas is investigated 500 ps after its preheating by a nonresonant short and intense laser pulse. The temperature of thermalization is optically determined with two additional short laser pulses enabling a field-free molecular alignment process and its probing, respectively. The measurements are performed for various intensities of the preheat pulse, leading to the observation of different temperatures which are in very good agreement with classical molecular dynamics simulations. The results can be regarded as a step towards real-time tracking of ultrafast relaxation pathways in molecular motion.
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Huet, T. R., Aviles Moreno, J. - R., Pirali, O., Tudorie, M., Partal Urena, F., & Lopez Gonzalez, J. - J. (2012). Terpenes in the gas phase: The Far-IR spectrum of perillaldehyde. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 113(11), 1261–1265.
Résumé: The far infrared spectrum of S-(-)-perillaldehyde, a monoterpene containing an aldehyde functional group, has been recorded in the gas phase using FTIR spectroscopy. The vibration signature of the three most populated rotamers has been observed and identified in the 30-650 cm(-1) range. The vibration assignment was based on the scaled B3LYP/cc-pVDZ harmonic force field of Partal Urena et al., 2008 [10]. Anharmonic contributions calculated at the HF/6-31+G* level were found negligible. (C) 2011 Elsevier Ltd. All rights reserved.
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Ideguchi, T., Bernhardt, B., Guelachvili, G., Haensch, T. W., & Picque, N. (2012). Raman-induced Kerr-effect dual-comb spectroscopy. OPTICS LETTERS, 37(21), 4498–4500.
Résumé: We report on the first (to our knowledge) demonstration of nonlinear dual-frequency-comb spectroscopy. In multi-heterodyne femtosecond Raman-induced Kerr-effect spectroscopy, the Raman gain resulting from the coherent excitation of molecular vibrations by a spectrally narrow pump is imprinted onto the femtosecond laser frequency comb probe spectrum. The birefringence signal induced by the nonlinear interaction of these beams and the sample is heterodyned against a frequency comb local oscillator with a repetition frequency slightly different from that of the comb probe. Such time-domain interference provides multiplex access to the phase and amplitude Raman spectra over a broad spectral bandwidth within a short measurement time. (C) 2012 Optical Society of America
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Ideguchi, T., Poisson, A., Guelachvili, G., Haensch, T. W., & Picque, N. (2012). Adaptive dual-comb spectroscopy in the green region. OPTICS LETTERS, 37(23), 4847–4849.
Résumé: Dual-comb spectroscopy is extended to the visible spectral range with two short-pulse frequency-doubled free-running ytterbium-doped fiber lasers. When the spectrum is shifted to other domains by nonlinear frequency conversion, tracking the relative fluctuations of the femtosecond oscillators at their fundamental wavelength automatically produces the correction signal needed for the recording of distortion-free spectra. The dense rovibronic spectrum of iodine around 19; 240 cm(-1) is recorded within 12 ms at Doppler-limited resolution. (C) 2012 Optical Society of America
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Lamouroux, J., Gamache, R. R., Laraia, A. L., Hartmann, J. - M., & Boulet, C. (2012). Semiclassical calculations of half-widths and line shifts for transitions in the 30012 <- 00001 and 30013 <- 00001 bands of CO2 II: Collisions with O-2 and air. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 113(11), 991–1003.
Résumé: The complex Robert-Bonamy (CRB) formalism was used to calculate the half-width, its temperature dependence, and the line shift for CO2 for transitions in the 30012 <- 00001 and 30013 <- 00001 bands with O-2 as the perturbing gas. The calculations were done for rotational quantum numbers from J=0 to J=120 with no ad hoc scaling of the line shape equations. The intermolecular potential parameters are adjusted on accurate experimental measurements of the half-widths, its temperature dependence, and the pressure-induced line shifts so that a single intermolecular potential reproduces all three parameters. Using the results of this work and previous results for N-2-broadening, air-broadening line shape parameters were also determined. The comparison of the CRB calculations with the experimental data available in the literature for the three line shape coefficients demonstrates the quality of the present calculations for the both bands under study. (C) 2012 Elsevier Ltd. All rights reserved.
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Martin-Drumel, M. A., Eliet, S., Pirali, O., Guinet, M., Hindle, F., Mouret, G., & Cuisset, A. (2012). New investigation on THz spectra of OH and SH radicals (X-2 Pi(i)). CHEMICAL PHYSICS LETTERS, 550, 8–14.
Résumé: Pure rotational transitions of OH and SH radicals have been recorded in the THz spectral range using cw-THz and synchrotron-based FT-FIR techniques. Line lists on these radicals have been completed in the three and two lowest vibrational states for OH and SH, respectively. Furthermore, the hyperfine structure of OH and SH has been observed for the first time using infrared IR FT-spectroscopy, and at frequencies higher than 1 THz, respectively. A combined fit has been made for each of these radicals including v = 0, 1 and 2 for OH and v = 0 and 1 for SH. (c) 2012 Elsevier B.V. All rights reserved.
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Mendes, L. A. V., Boye-Peronne, S., Jacovella, U., Lievin, J., & Gauyacq, D. (2012). Rydberg states of cyanoacetylene investigated by (3+1) REMPI spectroscopy in the 77,000-90,000 cm(-1) energy range. MOLECULAR PHYSICS, 110(21-22), 2829–2842.
Résumé: (3 + 1) resonantly enhanced multiphoton ionization (REMPI) spectroscopy coupled to photoelectron spectroscopy (REMPI-PES) has been carried out to study the Rydberg states of HC3N in the 77,000-90,000 cm(-1) region. Ab initio calculations (energies and optimized equilibrium geometries) have been performed for the first time for the low-lying (X) over tilde (2)Pi, (A) over tilde (2)Sigma(+) and (B) over tilde (2)Pi states of the cation HC3N+ in order to help the analysis. Thanks to the combination of the three-photon REMPI spectra, one-photon spectrum and photoelectron spectra, unambiguous assignments of the Rydberg series and their vibrationally excited members are proposed. The electronic Rydberg structure of cyanoacetylene is very similar to that of C2H2 and HCN (almost identical quantum defects), fully supporting the present analysis. New three-photon allowed Rydberg series are identified belonging to ns and nd series. The three-photon vibrational band assignments, confirmed by the photoelectrons spectra, reveal excitation of only one or two quanta of the nu(2) (C N) mode. Apparent discrepancies between the three-photon REMPI spectrum and the one-photon absorption spectrum are removed via a minor re-assignment of the absorption spectrum previously analysed by Connors et al. J. Chem. Phys. 60(12), 5011 (1974). Finally the observed analogy with C2H2 and HCN can be rationalized by a partial relocalization of the 2 pi electrons upon excitation to Rydberg states converging to the (X) over tilde (2)Pi state of HC3N+, as predicted by the present ab initio calculations on the cation core.
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Nguyen-Thi Van-Oanh, Falvo, C., Calvo, F., Lauvergnat, D., Basire, M., Gaigeot, M. - P., & Parneix, P. (2012). Improving anharmonic infrared spectra using semiclassically prepared molecular dynamics simulations. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 14(7), 2381–2390.
Résumé: Classical molecular dynamics is a convenient method for computing anharmonic infrared spectra of polyatomic molecules and condensed phase systems. However it does not perform well for predicting accurate intensities and it lacks nuclear quantization, two deficiencies that are usually accounted for by empirical scaling factors. In this paper we show on the examples of the trans isomer of nitrous acid and naphthalene that both issues can be alleviated by preparing the initial conditions according to semiclassical quantization based on a normal mode representation. The method correctly reproduces fundamental frequencies obtained with quantum mechanical methods. At increasing temperatures, the effective frequencies are found to follow the same trends as path-integral based methods. In the low-temperature limit, the band intensities predicted by the method are also found to agree with quantum mechanical considerations.
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Parneix, P., Basire, M., & Calvo, F. (2012). Time-resolved infrared emission spectra of naphthalene under gas phase laboratory and astrophysical conditions. COMPUTATIONAL AND THEORETICAL CHEMISTRY, 990, 112–118.
Résumé: The relaxation of neutral naphthalene C10H8 upon electronic excitation is theoretically modeled as a function of time by considering infrared emission cascade in competition with statistical dissociation, within the framework of kinetic Monte Carlo simulations. The possible importance of collisional energy transfer with a surrounding low-density medium is evaluated, and shown to agree with existing measurements. (C) 2011 Elsevier B.V. All rights reserved.
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Pirali, O., Boudon, V., Oomens, J., & Vervloet, M. (2012). Rotationally resolved infrared spectroscopy of adamantane. JOURNAL OF CHEMICAL PHYSICS, 136(2), 024310.
Résumé: We present the first rotationally resolved spectra of adamantane (C(10)H(16)) applying gas-phase Fourier transform infrared (IR) absorption spectroscopy. High-resolution IR spectra are recorded in the 33-4500 cm(-1)range using as source of IR radiation both synchrotron radiation (at the AILES beamline of the SOLEIL synchrotron) as well as a classical globar. Adamantane is a spherical top molecule with tetrahedral symmetry (T(d) point group) and has no permanent dipole moment in its vibronic ground state. Of the 72 fundamental vibrational modes in adamantane, only 11 are IR active. Here we present rotationally resolved spectra for seven of them: nu(30), nu(28), nu(27), nu(26), nu(25), nu(24), and nu(23). The typical rotational structure of spherical tops is observed and analyzed using the STDS software developed in the Dijon group, which provides the first accurate energy levels and rotational constants for seven fundamental modes. Rotational levels with quantum numbers as high as J = 107 have been identified and included in the fit leading to a typical standard deviation of about 10(-3) cm(-1).
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Quirico, E., Orthous-Daunay, F. - R., Bonal, L., Beck, P., Schmitt, B., Brunetto, R., Dartois, E., Pino, T., Engrand, C., & Duprat, J. (2012). THE MULTIPLE ORIGINS OF INSOLUBLE ORGANIC MATTER FROM PRIMITIVE CHONDRITES. METEORITICS & PLANETARY SCIENCE, 47, A323.
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Sanzharov, M., Vander Auwera, J., Pirali, O., Roy, P., Brubach, J. - B., Manceron, L., Gabard, T., & Boudon, V. (2012). Self and N-2 collisional broadening of far-infrared methane lines measured at the SOLEIL synchrotron. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 113(15), 1874–1886.
Résumé: Following our recent study devoted to measurements of intensities of pure rotation lines of methane, room temperature far infrared spectra of methane diluted in nitrogen at five total pressures between 100 and 800 hPa have been recorded at the AILES beamline of the SOLEIL synchrotron. One hundred and five N-2 broadening coefficients of methane pure rotation lines have been measured in the 83-261 cm(-1) spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles. Pressure-induced line shifts were not needed to fit the spectra to the noise level and line mixing effects were neglected. One hundred and seventy-six self broadening coefficients have also been measured in the 59-288 cm(-1) spectral range using the pure methane spectra recorded in our previous work. The measured N-2 broadening coefficients were compared to semi-classical calculations. (C) 2012 Elsevier Ltd. All rights reserved.
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Schliesser, A., Picque, N., & Haensch, T. W. (2012). Mid-infrared frequency combs. NATURE PHOTONICS, 6(7), 440–449.
Résumé: Laser frequency combs are coherent light sources that emit a broad spectrum of discrete, evenly spaced narrow lines whose absolute frequency can be measured to within the accuracy of an atomic clock. Their development in the near-infrared and visible domains has revolutionized frequency metrology while also providing numerous unexpected opportunities in other fields such as astronomy and attosecond science. Researchers are now exploring how to extend frequency comb techniques to the mid-infrared spectral region. Versatile mid-infrared frequency comb generators based on novel laser gain media, nonlinear frequency conversion or microresonators promise to significantly expand the applications of frequency combs. In particular, novel approaches to molecular spectroscopy in the 'fingerprint region', with dramatically improved precision, sensitivity, recording time and/or spectral bandwidth may lead to new discoveries in the various fields relevant to molecular science.
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Thibault, F., Gomez, L., Ivanov, S. V., Buzykin, O. G., & Boulet, C. (2012). Comparison of quantum, semi-classical and classical methods in the calculation of nitrogen self-broadened linewidths. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 113(15), 1887–1897.
Résumé: We perform dynamical calculations on two robust N-2-N-2 potential energy surfaces in order to intercompare pressure broadening coefficients derived from close coupling and coupled states quantum dynamical methods, the semi-classical model of Robert and Bonamy and a full classical method. The coupled states and full classical results compare well with the experimental results or with close coupling values when available. This study confirms that the classical method is a good alternative at room and high temperatures to quantum dynamical methods. The results obtained using the semi-classical method however deviate from the other sets of data at all temperatures considered here (77-2400 K). (C) 2012 Elsevier Ltd. All rights reserved.
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Tudorie, M., Ilyushin, V., Vander Auwera, J., Pirali, O., Roy, P., & Huet, T. R. (2012). Synchrotron FTIR spectroscopy of weak torsional bands: A case study of cis-methyl formate. JOURNAL OF CHEMICAL PHYSICS, 137(6), 064304.
Résumé: The far infrared spectrum of cis-methyl formate has been recorded on the AILES beamline of the synchrotron SOLEIL using a Fourier transform infrared spectrometer coupled to a long path cell. The very weak fundamental band associated with the methyl-top torsion mode (v(18)) was observed. The frequency analysis was performed using the “rho axis method”, and the microwave and millimeter-wave data from the literature. A precise determination of the band origins (v(18)(A) = 132.4303 cm(-1) and v(18)(E) = 131.8445 cm(-1)) and of the barrier height [V-3 = 370.7398 (58) cm(-1)] have been obtained. The intensity of the v(18) fundamental band was determined to be 3.4 x 10(-21) cm(-1)/(molecule cm(-2)) at 297 K, equally shared among A-A and E-E transitions, thus leading to a dipole moment component mu((3))(c) equal to 0.0483 D. The results were compared with the ab initio calculations of Senent et al. [Astrophys. J. 627, 567 (2005)]. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4740250]
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Turowski, M., Crepin, C., Douin, S., Gronowski, M., Couturier-Tamburelli, I., Pietri, N., Wasiak, A., & Kolos, R. (2012). Low temperature Raman spectra of cyanobutadiyne (HC5N). VIBRATIONAL SPECTROSCOPY, 62, 268–272.
Résumé: Low temperature Raman scattering spectra of cyanobutadiyne, either condensed from the vapour as a solid film, or isolated in a cryogenic argon matrix, have been measured – leading to the identification of all vibrational fundamentals, together with several overtones and combination modes. The analysis is based on previous experimental data, including the vibrationally resolved phosphorescence spectra, and on the comparison to available theoretical predictions. (C) 2012 Elsevier B.V. All rights reserved.
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Wakelam, V., Herbst, E., Loison, J. - C., Smith, I. W. M., Chandrasekaran, V., Pavone, B., Adams, N. G., Bacchus-Montabonel, M. - C., Bergeat, A., Beroff, K., Bierbaum, V. M., Chabot, M., Dalgarno, A., van Dishoeck, E. F., Faure, A., Geppert, W. D., Gerlich, D., Galli, D., Hebrard, E., Hersant, F., Hickson, K. M., Honvault, P., Klippenstein, S. J., Le Picard, S., Nyman, G., Pernot, P., Schlemmer, S., Selsis, F., Sims, I. R., Talbi, D., Tennyson, J., Troe, J., Wester, R., & Wiesenfeld, L. (2012). A KINETIC DATABASE FOR ASTROCHEMISTRY (KIDA). ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 199(1), 21.
Résumé: We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database for Astrochemistry (KIDA), this database consists of gas-phase reactions with rate coefficients and uncertainties that will be vetted to the greatest extent possible. Submissions of measured and calculated rate coefficients are welcome, and will be studied by experts before inclusion into the database. Besides providing kinetic information for the interstellar medium, KIDA is planned to contain such data for planetary atmospheres and for circumstellar envelopes. Each year, a subset of the reactions in the database (kida.uva) will be provided as a network for the simulation of the chemistry of dense interstellar clouds with temperatures between 10 K and 300 K. We also provide a code, named Nahoon, to study the time-dependent gas-phase chemistry of zero-dimensional and one-dimensional interstellar sources.
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Yu, S. S., Pearson, J. C., Drouin, B. J., Martin-Drumel, M. A., Pirali, O., Vervloet, M., Coudert, L. H., Muller, H. S. P., & Brunken, S. (2012). Measurement and analysis of new terahertz and far-infrared spectra of high temperature water. JOURNAL OF MOLECULAR SPECTROSCOPY, 279, 16–25.
Résumé: Terahertz absorption spectroscopy and far infrared Fourier transform (FIR-FT) emission spectroscopy were employed to measure new rotational and ro-vibrational spectra and validate existing datasets for high temperature water, with the goal to improve the accuracy of predictions for pure rotation in the (0 2 0), (1 0 0) and (0 0 1) vibrational states. A total of 104 new rotational transitions in (0 0 0), (0 1 0), (0 2 0), (1 0 0) and (0 0 1) were observed in the 293-2723 GHz region with MW accuracy and with observed J(Max) = 18, 11, 10, 14, 10; K-a(Max)= 10, 7, 7, 7, 4; E ''(Max)= 4178, 3771, 4996, 5430, 4939 cm(-1), respectively. A total of 4194 new FIR-FT transitions were assigned in the 50-600 cm(-1) region to the same five vibrational states with estimated experimental uncertainty of 0.0008-0.002 cm(-1) and with J(Max) = 27; K-a(Max) = 21, 18, 18, 17, 17, respectively. Together with previous high-resolution observations, these new data were fitted with the Bending-Rotation approach and the Euler Hamiltonian. The new measurements and predictions reported here will support the analyses of astronomical observations by high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA. (c) 2012 Elsevier Inc. All rights reserved.
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Actes de Conférences |
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Béroff K., Nguyen-Thi V.O., Chabot M., Pino T., Tuna T., Martinet G., LePadellec A., & Do Thi N. (2012). FRAGMENTATION OF MULTIPLY-CHARGED SMALL HYDROCARBONS MOLECULES CnHq+ (n=1-3, q=2-6) PRODUCED IN HIGH VELOCITY COLLISIONS: BRANCHING RATIOS AND ASSOCIATED KINETIC ENERGY RELEASE OF THE H+ FRAGMENT. In JOURNAL OF PHYSICS-CONFERENCE SERIES (Vol. 388, 102062).
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Chabot M., Béroff K., Pino T., Féraud G., Do Thi N., LePadellec A., Martinet G., Bouneau S., & Carpentier Y. (2012). NEGATIVE ION PRODUCTIONS IN HIGH VELOCITY COLLISIONS BETWEEN SMALL CARBON CLUSTERS AND HELIUM ATOME TARGET. In JOURNAL OF PHYSICS-CONFERENCE SERIES (Vol. 388, 102036).
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Ideguchi, T., Bernhardt, B., Guelachvili, G., Haensch, T. W., & Picque, N. (2012). Femtosecond stimulated Raman Dual-Comb Spectroscopy. In 2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO).
Résumé: Nonlinear dual-frequency-comb spectroscopy is demonstrated with multi-heterodyne femtosecond Raman-induced Kerr-effect spectroscopy. Spectra of liquid samples are recorded with a spectral resolution of 200 GHz, a measurement time of 350 μs and a sensitivity of 10(-6).
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Ideguchi, T., Poisson, A., Guelachvili, G., Haensch, T. W., & Picque, N. (2012). Real-time Dual-comb Spectroscopy of Iodine in the Visible. In 2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO).
Résumé: Dual-comb spectroscopy is extended to the visible range. The dense rovibronic spectrum of iodine around 520 nm is measured within 12 ms at Doppler-limited resolution with a scheme that only uses free-running lasers.
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Poisson, A., Ideguchi, T., Guelachvili, G., Picque, N., & Haensch, T. W. (2012). Adaptive Dual-comb Spectroscopy with Free-running Lasers and Resolved Comb Lines. In 2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO).
Résumé: A new scheme of real-time dual-comb spectroscopy that only uses free-running femtosecond lasers provides distortion-free Fourier spectra with resolved comb lines across the full spectral span of erbium-doped fiber lasers (>80 nm centered around 1550 nm) without a posteriori data processing.
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Quirico, E., Orthous-Daunay, F. - R., Bonal, L., & et al. (2012). THE MULTIPLE ORIGINS OF THE UNSOLUBLE ORGANIC MATTER FROM PRIMITRIVE CHONDRITES. In Meteoritics & Planetary Science (Vol. 47, A323).
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Wang, C. Y., Herr, T., Del'Haye, P., Schliesser, A., Holzwarth, R., Haensch, T. W., Picque, N., & Kippenberg, T. J. (2012). Generation of Low Phase-noise Mid-Infrared Optical Frequency Combs from Crystalline Microresonators. In 2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO).
Résumé: We present mid-infrared frequency comb generation from crystalline MgF2 microresonators, with mode spacing of 50-150 GHz around the 2.5 μm-wavelength CW-pump. Low phase-noise is verified by beating the comb modes with a narrow line width CW laser.
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