Peer-reviewed Publications |
Amyay B., Louviot M., Pirali O., Georges R., Vander Auwera J., & Boudon V. (2016). Global analysis of the high temperature infrared emission spectrum of 12CH4 in the dyad (ν2/ν4) region. JOURNAL OF CHEMICAL PHYSICS, 144(2), 024312.
Résumé: We report new assignments of vibration-rotation line positions of methane (12CH4) in the so-called dyad (ν2/ν4) region (1100–1500 cm−1), and the resulting update of the vibration-rotation effective model of methane, previously reported by Nikitin et al. [Phys. Chem. Chem. Phys. 15, 10071 (2013)], up to and including the tetradecad. High resolution (0.01 cm−1) emission spectra of methane have been recorded up to about 1400 K using the high-enthalpy source developed at Institut de Physique de Rennes associated with the Fourier transform spectrometer of the SOLEIL synchrotron facility (AILES beamline). Analysis of these spectra allowed extending rotational assignments in the well-known cold band (dyad-ground state (GS)) and related hot bands in the pentad–dyad system (3000 cm−1) up to Jmax = 30 and 29, respectively. In addition, 8512 new transitions belonging to the octad–pentad (up to J = 28) and tetradecad-octad (up to J = 21) hot band systems were successfully identified. As a result, the MeCaSDa database of methane was significantly improved. The line positions assigned in this work, together with the information available in the literature, were fitted using 1096 effective parameters with a dimensionless standard deviation σ = 2.09. The root mean square deviations dRMS are 3.60 × 10−3 cm−1 for dyad-GS cold band, 4.47 ×10−3 cm−1 for the pentad–dyad, 5.43 × 10−3 cm−1 for the octad–pentad, and 4.70 × 10−3 cm−1 for the tetradecad–octad hot bands. The resulting new line list will contribute to improve opacity and radiative transfer models for hot atmospheres, such as those of hot-Jupiter type exoplanets.
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Asselin, P., Madebene, B., Soulard, P., Georges, R., Goubet, M., Huet, T. R., Pirali, O., & Zehnacker-Rentien, A. (2016). Competition between inter- and intra-molecular hydrogen bonding: An infrared spectroscopic study of jet-cooled amino-ethanol and its dimer. Journal Of Chemical Physics, 145(22), 224313.
Résumé: The Fourier transform IR vibrational spectra of amino-ethanol (AE) and its dimer have been recorded at room temperature and under jet-cooled conditions over the far and mid infrared ranges (50-4000 cm(-1)) using the White-type cell and the supersonic jet of the Jet-AILES apparatus at the synchrotron facility SOLEIL. Assignment of the monomer experimental frequencies has been derived from anharmonic frequencies calculated at a hybrid CCSD(T)-F12/MP2 level. Various thermodynamical effects in the supersonic expansion conditions including molar dilution of AE and nature of carrier gas have been used to promote or not the formation of dimers. Four vibrational modes of the observed dimer have been unambiguously assigned using mode-specific scaling factors deduced from the ratio between experimental and computed frequencies for the monomer. The most stable g 'Gg' monomer undergoes strong deformation upon dimerization, leading to a homochiral head to head dimer involving two strong hydrogen bonds. Published by AIP Publishing.
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Baczko, K., Fensterbank, H., Berini, B., Bordage, N., Clavier, G., Meallet-Renault, R., Larpent, C., & Allard, E. (2016). Azide-Functionalized Nanoparticles as Quantized Building Block for the Design of Soft-Soft Fluorescent Polystyrene Core-PAMAM Shell Nanostructures. Journal Of Polymer Science Part A-Polymer Chemistry, 54(1), 115–126.
Résumé: This work deals with the covalent coupling of azide-functionalized polymeric nanoparticles as a reactive core and amino-terminated PAMAM dendrons as a reactive shell. The nanoassemblies thereby obtained could be modified after the dendronization step by grafting an alkynyl Bodipy dye on the unreacted azide moieties. Only a few steps are required to attain nanoassemblies that could mimic dendrimers of high generation with sizes of nano-objects beyond those of dendrimers. The structure of the nanoassemblies are composed of a polystyrene core, an inner shell including the Bodipy dyes along with the internal branches of the PAMAM, and the terminal amino groups from the outer shell. The dendritic shell acts as a protective layer that prevents NP from aggregation in a surfactant free aqueous solution. The nano-objects display absorption and emission maxima above 500 nm with brightness that are the same order of magnitude than Qdots. (C) 2015 Wiley Periodicals, Inc.
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Bergeron, H., Curado, E. M. F., Gazeau, J. P., & Rodrigues, L. M. C. S. (2016). Extensivity of Rényi entropy for the Laplace–de Finetti distribution. Physica A: Statistical Mechanics and its Applications, 441, 23–31.
Résumé: The Boltzmann Gibbs entropy is known to be asymptotically extensive for the Laplace de Finetti distribution. We prove here that the same result holds in the case of the Renyi entropy. We also show some interesting lower and upper bounds for the asymptotic limit of these entropies. (C) 2015 Elsevier B.V. All rights reserved.
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Bergeron, H., Curado, E. M. F., Gazeau, J. P., & Rodrigues, L. M. C. S. (2016). Symmetric deformed binomial distributions: An analytical example where the Boltzmann-Gibbs entropy is not extensive. Journal of Mathematical Physics, 57(2), 023301.
Résumé: Asymptotic behavior (with respect to the number of trials) of symmetric generalizations of binomial distributions and their related entropies is studied through three examples. The first one has the q-exponential as the generating function, the second one involves the modified Abel polynomials, and the third one has Hermite polynomials. We prove analytically that the Renyi entropy is extensive for these three cases, i.e., it is proportional (asymptotically) to the number n of events and that q-exponential and Hermite cases have also extensive Boltzmann-Gibbs. The Abel case is exceptional in the sense that its Boltzmann-Gibbs entropy is not extensive and behaves asymptotically as the square root of n. This result is obtained numerically and also confirmed analytically, under reasonable assumptions, by using a regularization of the beta function and its derivative. Probabilistic urn and genetic models are presented for illustrating this remarkable case. (C) 2016 AIP Publishing LLC.
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Bergeron, H., Czuchry, E., Gazeau, J. - P., & Malkiewicz, P. (2016). Nonadiabatic bounce and an inflationary phase in the quantum mixmaster universe. Physical Review D, 93(12), 043521.
Résumé: Following our previous paper, Bergeron et al., Smooth quantum dynamics of the mixmaster universe, Phys. Rev. D 92, 061302(R) (2015), concerning the quantization of the vacuum Bianchi IX model and the Born-Huang-Oppenheimer framework, we present a further analysis of the dynamical properties of the model. Consistently with the deep quantum regime, we implement the harmonic approximation of the anisotropy potential. We thus obtain manageable dynamical equations. We study the quantum anisotropic oscillations during the bouncing phase of the universe. Neglecting the backreaction from transitions between quantum anisotropy states, we obtain analytical results. In particular, we identify a parameter that is associated with dynamical properties of the quantum model and describes a sort of phase transition. Once the parameter exceeds its critical value, the Born-Huang-Oppenheimer approximation breaks down. The application of the present result to a simple model of the universe indicates that the parameter indeed exceeds its critical value and that there takes place a huge production of anisotropy at the bounce. This in turn must lead to a sustained phase of accelerated expansion, an inflationary phase. The quantitative inclusion of backreaction shall be examined in a follow-up paper based on the vibronic approach.
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Bergeron, H., Czuchry, E., Gazeau, J. - P., & Malkiewicz, P. (2016). Vibronic framework for quantum mixmaster universe. Physical Review D, 93(6), 064080.
Résumé: Following our previous papers concerning the quantization of the vacuum Bianchi-IX model within or beyond the Born-Oppenheimer and adiabatic approximation, we develop a more elaborate analysis of the dynamical properties of the model based on the vibronic approach utilized in molecular physics. As in the previous papers, we restrict our approach to the harmonic approximation of the anisotropy potential in order to obtain resoluble analytical expressions.
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Bizau, J. M., Cubaynes, D., Guilbaud, S., El Hassan, N., Al Shorman, M. M., Bouisset, E., Guigand, J., Moustier, O., Marie, A., Nadal, E., Robert, E., Nicolas, C., & Miron, C. (2016). A merged-beam setup at SOLEIL dedicated to photoelectron-photoion coincidence studies on ionic species. Journal Of Electron Spectroscopy And Related Phenomena, 210, 5–12.
Résumé: We describe the merged-beam setup permanently installed on a dedicated optical branch of the PLEIADES beamline at SOLEIL, the French synchrotron radiation facility in St-Aubin, delivering photons in the 10-1000 eV photon energy range. The setup is designed both for photoion and photoelectron spectroscopy experiments on atomic and molecular ions. Ion spectrometry is dedicated to the deterrnination of absolute single and multiple photoionization cross sections. Electron spectroscopy brings additional information on the non-radiative decay of inner-vacancies produced in the photoionization processes and allows for the determination of partial cross sections. Efficient reduction of the background in the electron spectra is achieved by the use of the electron-ion coincidence technique. Examples of photoion and photoelectron spectra are given for the Xe5+ ion. (C) 2016 Elsevier B.V. All rights reserved.
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Bizau, J. M., Cubaynes, D., Guilbaud, S., Penent, F., Lablanquie, P., Andric, L., Palaudoux, J., Al Shorman, M. M., & Blancard, C. (2016). Photoelectron Spectroscopy of Ions: Study of the Auger Decay of the 4d -> nf (n=4,5) Resonances in Xe5+ Ion. Physical Review Letters, 116(10), 103001.
Résumé: We have studied, for the first time by electron spectroscopy, the Auger decay of the 4d -> nf ( n = 4,5) resonances in Xe5+ ion. By detecting in coincidence the Auger electrons with the resulting Xe6+ ions, we unravel the contribution of the different final ionic states to the total cross section measured by ion spectroscopy. A strong intensity of 5s5p satellite lines has been observed, up to 4 times stronger than the 5s(2) main lines. This unexpected behavior is confirmed by multiconfiguration Dirac- Fock calculations. This technique provides the most stringent test for theoretical models and allows us to disentangle the contribution of ions in the ground and metastable states in the target beam.
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Bobrov, K., Kalashnyk, N., & Guillemot, L. (2016). Thermodynamic balance of perylene self-assembly on Ag(110). J Chem Phys, 145(15), 154705.
Résumé: We present a room temperature STM study of perylene adsorption on Ag(110) at the monolayer coverage regime. We found that structure and symmetry of the perylene monolayer are settled by thermodynamic balance of the three factors: (i) the ability of perylene molecules to recognize specific adsorption sites on the (110) lattice, (ii) the intermolecular interaction, and (iii) the accommodation of thermal motion of the molecules. The moderate strength of the site recognition and the intermolecular interaction, of the same order of magnitude as kT approximately 25 meV, represents a key feature of the thermodynamic balance. It bestows to this system the unique quality to form the quasi-liquid monolayer of epitaxial as well as self-assembling character. The perylene monolayer accommodates the short-range motion of the molecules instead of quenching it. It precludes the formation of possible solid nuclei and maintains common registry of the included molecules. The surface registry of the quasi-liquid phase is provided by locking of a structure-related fraction of the perylene molecules into specific adsorption sites of the (110) lattice favorable in terms of intermolecular interaction.
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Boudjemaa, R., Briandet, R., Revest, M., Jacqueline, C., Caillon, J., Fontaine-Aupart, M. P., & Steenkeste, K. (2016). New Insight into Daptomycin Bioavailability and Localization in Staphylococcus aureus Biofilms by Dynamic Fluorescence Imaging. Antimicrobial Agents And Chemotherapy, 60(8), 4983–4990.
Résumé: Staphylococcus aureus is one of the most frequent pathogens responsible for biofilm-associated infections (BAI), and the choice of antibiotics to treat these infections remains a challenge for the medical community. In particular, daptomycin has been reported to fail against implant-associated S. aureus infections in clinical practice, while its association with rifampin remains a good candidate for BAI treatment. To improve our understanding of such resistance/ tolerance toward daptomycin, we took advantage of the dynamic fluorescence imaging tools (time-lapse imaging and fluorescence recovery after photobleaching [FRAP]) to locally and accurately assess the antibiotic diffusion reaction in methicillin-susceptible and methicillin-resistant S. aureus biofilms. To provide a realistic representation of daptomycin action, we optimized an in vitro model built on the basis of our recently published in vivo mouse model of prosthetic vascular graft infections. We demonstrated that at therapeutic concentrations, daptomycin was inefficient in eradicating biofilms, while the matrix was not a shield to antibiotic diffusion and to its interaction with its bacterial target. In the presence of rifampin, daptomycin was still present in the vicinity of the bacterial cells, allowing prevention of the emergence of rifampin-resistant mutants. Conclusions derived from this study strongly suggest that S. aureus biofilm resistance/ tolerance toward daptomycin may be more likely to be related to a physiological change involving structural modifications of the membrane, which is a strain-dependent process.
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Boudon, V., Lamy, M., Dugue-Boyé, F., Pirali, O., Gruet, S., D’Accolti, L., Fusco, C., Annese, C., & Alikhani, M. E. (2016). Synthesis, High-Resolution Infrared Spectroscopy, and Vibrational Structure of Cubane, C8H8. The Journal of Physical Chemistry A, 120(25), 4418–4428.
Résumé: Carbon-cage molecules have generated a considerable interest from both experimental and theoretical points of view. We recently performed a high-resolution study of adamantane (C10H16), the smallest hydrocarbon cage belonging to the diamandoid family (Pirali, O.; et al. J. Chem. Phys. 2012, 136, 024310). There exist another family of hydrocarbon cages with additional interesting chemical properties: the so-called platonic hydrocarbons that comprise dodecahedrane (C20H20) and cubane (C8H8). Both possess C–C bond angles that deviate from the tetrahedral angle (109.8°) of the sp3 hybridized form of carbon. This generates a considerable strain in the molecule. We report a new wide-range high-resolution study of the infrared spectrum of cubane. The sample was synthesized in Bari upon decarboxylation of 1,4-cubanedicarboxylic acid thanks to the improved synthesis of literature. Several spectra have been recorded at the AILES beamline of the SOLEIL synchrotron facility. They cover the 600–3200 cm–1 region. Besides the three infrared-active fundamentals (ν10, ν11, and ν12), we could record many combination bands, all of them displaying a well-resolved octahedral rotational structure. We present here a preliminary analysis of some of the recorded bands, performed thanks the SPVIEW and XTDS software, based on the tensorial formalism developed in the Dijon group. A comparison with ab initio calculations, allowing to identify some combination bands, is also presented.
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Boulet, C., & Ma, Q. (2016). The relaxation matrix for symmetric tops with inversion symmetry. II. Line mixing effects in the ν1 band of NH3. JOURNAL OF CHEMICAL PHYSICS, 144(22), 224304.
Résumé: Line mixing e ects have been calculated in the ν1 parallel band of self-broadened NH3. The theoretical approach is an extension of a semi-classical model to symmetric-top molecules with inversion symmetry developed in the companion paper [Q. Ma and C. Boulet, J. Chem. Phys. 144, 224303 (2016)]. This model takes into account line coupling e ects and hence enables the calculation of the entire relaxation matrix. A detailed analysis of the various coupling mechanisms is carried out for Q and R inversion doublets. The model has been applied to the calculation of the shape of the Q branch and of some R manifolds for which an obvious signature of line mixing e ects has been experimentally demonstrated. Comparisons with measurements show that the present formalism leads to an accurate prediction of the available experimental line shapes. Discrepancies between the exper- imental and theoretical sets of rst order mixing parameters are discussed as well as some extensions of both theory and experiment.
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Broquier, M., Soorkia, S., Dedonder-Lardeux, C., Jouvet, C., Theule, P., & Gregoire, G. (2016). Twisted Intramolecular Charge Transfer in Protonated Amino Pyridine. J. Phys. Chem. A, 120(21), 3797–3809.
Résumé: The excited state properties of protonated ortho (2-), meta (3-), and para (4-) aminopyridine molecules have been investigated through UV photofragmentation spectroscopy and excited state coupled-cluster CC2 calculations. Cryogenic ion spectroscopy allows recording well-resolved vibronic spectroscopy that can be reproduced through Franck-Condon simulations of the pipi* local minimum of the excited state potential energy surface. The excited state lifetimes have also been measured through a pump-probe excitation scheme and compared to the estimated radiative lifetimes. Although protonated aminopyridines are rather simple aromatic molecules, their deactivation mechanisms are indeed quite complex with unexpected results. In protonated 3- and 4-aminopyridine, the fragmentation yield is negligible around the band origin, which implies the absence of internal conversion to the ground state. Besides, a twisted intramolecular charge transfer reaction is evidenced in protonated 4-aminopyridine around the band origin, while excited state proton transfer from the pyridinic nitrogen to the adjacent carbon atom opens with roughly 500 cm-1 of excess energy.
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Canneson, D., Le Moal, E., Cao, S., Quélin, X., Dallaporta, D., Dujardin, G., & Boer-Duchemin, E. (2016). Surface plasmon polariton beams from an electrically excited plasmonic crystal. Opt. Express, 24(23), 26186–26200.
Résumé: Surface plasmon polariton (SPP) beams with an in-plane angular spread of 8° are
produced by electrically exciting a 2D plasmonic crystal using a scanning tunneling microscope (STM). The plasmonic crystal consists of a gold nanoparticle (NP) array on a thin gold film on a glass substrate and it is the inelastic tunnel electrons (IET) from the STM that provide a localized and spectrally broadband SPP source. Surface waves on the gold film are shown to be essential for the coupling of the local, electrical excitation to the extended NP array, thus leading to the creation of SPP beams. A simple model of the scattering of SPPs by the array is used to explain the origin and direction of the generated SPP beams under certain conditions. In order to take into account the broadband spectrum of the source, calculations realized using finite-difference time-domain (FDTD) methods are obtained, showing that bandgaps for SPP propagation exist for certain wavelengths and indicating how changing the pitch of the NP array may enhance the SPP beaming effect.
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Capello, M. C., Hernandez, F. J., Broquier, M., Dedonder-Lardeux, C., Jouvet, C., & Pino, G. A. (2016). Hydrogen bonds vs. pi-stacking interactions in the p-aminophenol ... p-cresol dimer: an experimental and theoretical study. Physical Chemistry Chemical Physics, 18(45), 31260–31267.
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Carcabal, P., Descamps, D., Petit, S., Mairesse, Y., Blanchet, V., & Cireasa, R. (2016). Using high harmonic radiation to reveal the ultrafast dynamics of radiosensitiser molecules. Faraday Discussions, 194, 407–425.
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Cazaux, S., Boschman, L., Rougeau, N., Reitsma, G., Hoekstra, R., Teillet-Billy, D., Morisset, S., Spaans, M., & Schlatholter, T. (2016). The sequence to hydrogenate coronene cations: A journey guided by magic numbers. Sci Rep, 6, 19835.
Résumé: The understanding of hydrogen attachment to carbonaceous surfaces is essential to a wide variety of research fields and technologies such as hydrogen storage for transportation, precise localization of hydrogen in electronic devices and the formation of cosmic H2. For coronene cations as prototypical Polycyclic Aromatic Hydrocarbon (PAH) molecules, the existence of magic numbers upon hydrogenation was uncovered experimentally. Quantum chemistry calculations show that hydrogenation follows a site-specific sequence leading to the appearance of cations having 5, 11, or 17 hydrogen atoms attached, exactly the magic numbers found in the experiments. For these closed-shell cations, further hydrogenation requires appreciable structural changes associated with a high transition barrier. Controlling specific hydrogenation pathways would provide the possibility to tune the location of hydrogen attachment and the stability of the system. The sequence to hydrogenate PAHs, leading to PAHs with magic numbers of H atoms attached, provides clues to understand that carbon in space is mostly aromatic and partially aliphatic in PAHs. PAH hydrogenation is fundamental to assess the contribution of PAHs to the formation of cosmic H2.
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Chagas, G. R., Xie, X., Darmanin, T., Steenkeste, K., Gaucher, A., Prim, D., Meallet-Renault, R., Godeau, G., Amigoni, S., & Guittard, F. (2016). Electrodeposition of Polypyrenes with Tunable Hydrophobicity, Water Adhesion, and Fluorescence Properties. Journal Of Physical Chemistry C, 120(13), 7077–7087.
Résumé: The control in surface hydrophobicity and water adhesion is extremely important for various applications in water harvesting, oil/water separation membrane, energy systems or biosensing, for example. Here, for the first time we show that the use of fluorescent monomers such as pyrene with various substituents differing by their hydrophobicity, size, or rigidity/flexibility can lead to surfaces with tunable hydrophobicity, water adhesion and fluorescence properties by a direct electropolymerization process. Seven original monomers with fluoroalkyl, alkyl, phenyl, adamantyl, and triethylene glycol substituents were synthesized and studied. The surface roughness is highly dependent on the substituent, and it seems that the fluorescence, although complex, correlates with the surface roughness. Superhydrophobic properties and highly oleophobic properties are obtained using fluoroalkyl chains due to the presence of nanostructured microparticles. In comparison to the structured absorption and emission bands of pyrene monomers, the pyrene polymers (oligomers) exhibit a broad structureless spectral shape both in absorption and in emission, which seems to be due to pyrene oligomerization and aggregation. This work is a first tentative attempt to combine superhydrophobic and fluorescent properties using an innovative strategy and opens new doors to explore in this domain.
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Choi, D. - J., Robles, R., Gauyacq, J. - P., Rubio-Verdu, C., Lorente, N., & Ignacio Pascual, J. (2016). Spin-polarised edge states in atomic Mn chains supported on Cu2N/Cu (100). J. Phys. Condens. Matter., 28(23), 23lt01.
Résumé: Scanning tunnelling microscopy and density functional theory studies of manganese chains adsorbed on Cu2N/Cu (100) reveal an unsuspected electronic edge state at [Formula: see text] eV above the Fermi energy. This Tamm-like state is strongly localised to the terminal Mn atoms of the chain and fully spin polarised. However, no equivalence is found for occupied states, and the electronic structure at [Formula: see text] -1 eV is mainly spin unpolarised due to the extended p-states of the N atoms that mediate the coupling between the Mn atoms in the chain. The spin polarisation of the edge state is affected by the antiferromagnetic ordering of the chains leading to non-trivial consequences.
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Choi, D. - J., Robles, R., Gauyacq, J. - P., Ternes, M., Loth, S., & Lorente, N. (2016). Structural and magnetic properties of FeMnx chains (x=1–6) supported on Cu2N/Cu (100). Phys. Rev. B, 94(8), 085406.
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Cojocaru, G. V., Ungureanu, R. G., Banici, R. A., Ursescu, D., Guilbaud, O., Delmas, O., Le Marec, A., Neveu, O., Demailly, J., Pittman, M., Kazamias, S., Daboussi, S., Cassou, K., Li, L., Klisnick, A., Zeitoun, P., & Ros, D. (2016). One long and two short pumping pulses control for plasma x-ray amplifier optimization. Optics Express, 24(13), 14260–14270.
Résumé: Development of efficient soft x-ray laser plasma amplifiers adapted to seeded operation, requires a better control over amplifier transverse spatial extent, brilliance control and gain lifetime. Here it is shown that pumping the plasma amplifier with one long and two short pump pulses (1L2S) provides advantages in terms of control for the specified parameters in the case of Ni-like Ag x-ray laser. Also, significant tunability of the gain lifetime in the 1L2S pumping scheme for Ne-like Ti x-ray laser is observed. Direct harmonics seeding and chirped harmonics seeding amplification approaches may benefit from the control of the gain lifetime, in terms of better use of the pump energy and as a way to reduce the amplified spontaneous emission in x-ray lasers. (C) 2016 Optical Society of America
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Conte, C., Fotticchia, I., Tirino, P., Moret, F., Pagano, B., Gref, R., Ungaro, F., Reddi, E., Giancola, C., & Quaglia, F. (2016). Cyclodextrin-assisted assembly of PEGylated polyester nanoparticles decorated with folate. Colloids And Surfaces B-Biointerfaces, 141, 148–157.
Résumé: In the last decades, nano-oncologicals bearing a polyethylene glycol (PEG) coating are being emerging as biomimetic devices able to drive their drug cargo to solid tumors through passive mechanisms. To improve selectivity toward cancer cells, nanocarriers decorated with the small ligand folate have been widely investigated. Nevertheless, a great challenge remains the effective exposition of folate on nanoparticles (NPs), which is a key prerequisite to ensure the correct binding to receptor and the following endocytic uptake. On these premises, in this study we propose a novel strategy to produce core-shell folate-targeted NPs based on diblock copolymers of poly(epsilon-caprolactone) (PCL) and PEG through the aid of (2-hydroxypropyl)-beta-cyclodextrin (HPPCD). PCL4300-PEG(2000) and PCL4300-PEG(2000)-Fol copolymers were synthesized, characterized and employed to produce NPs without and with HP beta CD by a melting/sonication procedure. Colloidal properties of targeted NPs produced with HP beta CD demonstrated a highly extended conformation of PEG chains in the shell, an enhanced interaction with a specific antibody against folate and a higher uptake in cells overexpressing folate receptor. Overall, these results suggest that proper manipulation of PEG shell conformation through HP beta CD can represent a novel non-covalent strategy to modify shell features. (C) 2016 Elsevier B.V. All rights reserved.
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Coudert, L. H. (2016). The bending potential energy function of HDO obtained from high-resolution data. Journal of Molecular Spectroscopy, 330, 112–119.
Résumé: Line position and line intensity analyses of the high-resolution spectrum of the HDO isotopic species of the water molecule are performed with an extended version of the Bending-Rotation approach up to the (0 1 0) state and J = 22 . The line position analysis involves 3992 microwave, far infrared and infrared lines, and 421 experimental energy levels which were reproduced with a 1.1 unitless standard deviation. The data set considered in the line intensity analysis consists of 1405 infrared absorpon lines and 4 Stark coefficients fitted with a 1.2 unitless standard deviation. The results of both analyses are compared with previous investigations and are used to build a spectroscopic database which is compared with other available databases and should be useful for interpreting measurements carried out with the Infrared Atmospheric Sounding Interferometer (IASI).
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Cuisset, A., Coeur, C., Mouret, G., Ahmad, W., Tomas, A., & Pirali, O. (2016). Infrared spectroscopy of methoxyphenols involved as atmospheric secondary organic aerosol precursors: Gas-phase vibrational cross-sections. Journal of Quantitative Spectroscopy and Radiative Transfer, 179, 51–58.
Résumé: Methoxyphenols are emitted in the atmosphere from biomass burning and recent works have shown the potential role of these oxygenated aromatic species in the formation of secondary organic aerosols. IR spectroscopic data that would enable their remote measurement in the atmosphere remain scarce in the literature. Room temperature Far-IR cross-sections of 4 methoxyphenols (2-methoxyphenol or guaiacol, 3-methoxyphenol, 4-methoxyphenol and 2,6-dimethoxyphenol or syringol) have been determined using the THz synchrotron radiation available at SOLEIL. Mid- and near-IR regions have also been investigated with a conventional Fourier transform IR setup and allowed to provide a set of vibrational cross-sections of the studied methoxyphenols. Finally, gas-phase cross sections of two nitroguaiacol isomers (4-nitroguaiacol and 5-nitroguaiacol), two intermediate products involved in the formation of secondary organic aerosols have been measured in the mid- and near-IR with a heated multi-pass cell. Harmonic and anharmonic density functional theory calculations were carried out for all the studied compounds and allowed a full assignment of the recorded rovibrational bands.
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De la Lande, A., Ha-Thi, M. H., Chen, S. F., Soep, B., & Shafizadeh, N. (2016). Structure of cobalt protoporphyrin chloride and its dimer, observation and DFT modeling. Phys. Chem. Chem. Phys., 18(25), 16700–16708.
Résumé: In this article we present a joint study by time-of-flight mass spectroscopy and density functional theory of cobalt protoporphyrin dimer complexes. The main novelty of the experimental part is to reveal the formation of porphyrin dimers that eventually include a chlorine atom. Density functional theory calculations have been performed to shed light on the structural and electronic properties of monomers and dimers that may be formed experimentally. Various geometries of the monomers are analyzed in the two lowest spin states. The electronic structures are examined by means of population analysis relying on the iterative Hirshfeld scheme and the topological analyses of the electron localization function. It is shown that the cobalt ligand bond is purely ionic in the triplet states but shows a noticeable covalent character in the singlet state. Ionization potential of Co-protoporphyrin and binding energies of the chlorine ligand are also reported. Concerning the dimers, several association patterns are investigated for the chlorinated and non-chlorinated complexes. It is found that the structures of the most stable complexes involve four hydrogen bonds between the carboxylic acid moieties of the protoporphyrins. However other association modes are likely to be possible in the experiments.
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Debiossac, M., Zugarramurdi, A., Mu, Z., Lunca-Popa, P., Mayne, A. J., & Roncin, P. (2016). Helium diffraction on SiC grown graphene: Qualitative and quantitative descriptions with the hard-corrugated-wall model. PHYSICAL REVIEW B, 94(20), 205403.
Résumé: Monolayer epitaxial graphene grown on 6H-SiC(0001) was recently investigated by grazing-incidence fastatom diffraction and analyzed with an ab initio electronic density calculation and with exact atomic diffraction methods. With these results as a reference, the hard-corrugated-wall model (HCW) is used as a complementary analytic approach to link binary potentials to the observed atomic corrugation. The main result is that the HCW model reproduces the macroscopic corrugation of the moir´e pattern on a quantitative level, suggesting that soft-wall corrections may be neglected for macroscopic superstructures, allowing straightforward analysis in terms of a one-dimensional corrugation function.
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Decleva, P., Orr-Ewing, A. J., Kowalewski, M., Kornilov, O., Marangos, J. P., Worner, H. J., Johnson, A. S., Forbes, R., Rolles, D., Townsend, D., Schalk, O., Mai, S., Penfold, T. J., Miller, R. J. D., Centurion, M., Ueda, K., Domcke, W., Weber, P. M., Baeck, K. K., Travnikova, O., Liekhus-Schmaltz, C., Figueira, J. A. P., Neumark, N. D. M., Gessner, O., Stolow, A., Rudenko, A., Mishra, P. K., Kirrander, A., Dowek, D., Martin, F., Vibok, A., Minitti, M. P., Stankus, B., & Burger, C. (2016). Structural dynamics: general discussion. Faraday Discussions, 194, 583–620.
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Decleva, P., Quadri, N., Perveaux, A., Lauvergnat, D., Gatti, F., Lasorne, B., Halasz, G. J., & Vibok, A. (2016). Attosecond electronic and nuclear quantum photodynamics of ozone monitored with time and angle resolved photoelectron spectra. Scientific Reports, 6, 36613.
Résumé: Recently we reported a series of numerical simulations proving that it is possible in principle to create an electronic wave packet and subsequent electronic motion in a neutral molecule photoexcited by a UV pump pulse within a few femtoseconds. We considered the ozone molecule: for this system the electronic wave packet leads to a dissociation process. In the present work, we investigate more specifically the time-resolved photoelectron angular distribution of the ozone molecule that provides a much more detailed description of the evolution of the electronic wave packet. We thus show that this experimental technique should be able to give access to observing in real time the creation of an electronic wave packet in a neutral molecule and its impact on a chemical process.
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Del Cueto, M. M., AS Fuchsel, G Gatti, F Martin, F Diaz, C AF del Cueto, M. Muzas, A. S. Fuechsel, G. Gatti, F. Martin, F. Diaz. (2016). Role of van der Waals forces in the diffraction of noble gases from metal surfaces. PHYSICAL REVIEW B, 93(6), 060301.
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Depauw, A., Dossi, E., Kumar, N., Fiorini-Debuisschert, C., Huberfeld, G., Ha-Thi, M. - H., Rouach, N., & Leray, I. (2016). A Highly Selective Potassium Sensor for the Detection of Potassium in Living Tissues. Chem. Eur. J., 22(42), 14902–14911.
Résumé: The development of highly selective sensors for potassium is of great interest in biology. Two new hydrosoluble potassium sensors (Calix-COU-Alkyne and Calix-COU-Am) based on a calix[4]arene bis(crown-6) and an extended coumarin were synthesized and characterized. The photophysical properties and complexation studies of these compounds have been investigated and show high molar extinction coefficients and high fluorescence quantum yields. Upon complexation with potassium in the millimolar concentration range, an increase of one- and two-photon fluorescence emission is detected. A twofold fluorescence enhancement is observed upon excitation at λ=405 nm. The ligands present excellent selectivity for potassium in the presence of various competitive cations in water and in a physiological medium. The photophysical properties are not affected by the presence of a large amount of competing cations (Na+, Ca2+, Mg2+, etc.). Ex vivo measurements on mouse hippocampal slices show that Calix-COU-Alkyne accumulates extracellularly and does not alter the neuronal activity. Furthermore, the sensor can be utilized to monitor slow extracellular K+ increase induced by inhibition of K+ entry into the cells.
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Desrier, A., Romanzin, C., Lamarre, N., Alcaraz, C., Gans, B., Gauyacq, D., Liévin, J., & Boyé-Péronne, S. (2016). Experimental and ab initio characterisation of HC3N+ vibronic structure: I-Synchrotron-based Threshold Photo-Electron Spectroscopy. JOURNAL OF CHEMICAL PHYSICS, 145, 234310.
Résumé: Threshold-photoionization spectroscopy of cyanoacetylene (HC3N) and its 15N isotopologue has been investigated in the vacuum-ultraviolet range with a synchrotron- based experiment allowing to record threshold-photoelectron spectrum and photoion yield over a large energy range (from 88500 to 177500 cm−1, i.e. from 11 to 22 eV). Adiabatic ionization energies towards the three lowest electronic states X+ 2Π, A+ 2Σ+ and B+ 2Π are derived from the threshold-photoelectron spectrum. A detailed description of the vibrational structure of these states is proposed leading to the determination of the vibrational frequencies for most modes. The vibrational assignments and the discussion about the electronic structure are supported by multireference ab initio calculations (CASPT2, MRCI). Unprecedented structures are resolved and tentatively assigned in the region of the B+ ← X transition. Exploratory calculations highlight the complexity of the electronic landscape of the cation up to approximately 10 eV above its ground state.
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Ding, J. X., Cheng, Y. L., Li, M. Q., Gref, R., & Chen, X. S. (2016). Smart Polymeric Nanocarriers. Journal Of Nanomaterials, .
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Duchene, D., & Gref, R. (2016). Small is beautiful: Surprising nanoparticles. International Journal Of Pharmaceutics, 502(1-2), 219–231.
Résumé: In the preparation of nanoparticles for drug delivery, it is well known that their size as well as their surface decorations can play a major role in interaction with living media. It is less known that their shape and internal structure can interplay with cellular and in vivo fate. The scientific literature is full of a large variety of surprising terms referring to their shape and structure. The aim of this review is to present some examples of the most often encountered surprising nanoparticles prepared and usable in the pharmaceutical technology domain. They are presented in two main groups related to their physical aspects: 1) smooth surface particles, such as Janus particles, “snowmen”, “dumbbells”, “rattles”, and “onions” and 2) branched particles, such as “flowers”, “stars” and “urchins”. The mode of preparation and potential applications are briefly presented. The topic has a serious, wider importance, namely in opportunity these structures have to allow exploration of the role of shape and structure on the utility (and perhaps toxicity) of these nanostructures. (C) 2016 Elsevier B.V. All rights reserved.
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Duchene, D., Cavalli, R., & Gref, R. (2016). Cyclodextrin-based Polymeric Nanoparticles as Efficient Carriers for Anticancer Drugs. Current Pharmaceutical Biotechnology, 17(3), 248–255.
Résumé: Among the difficulties encountered in the treatment of cancer are the physico-chemical properties of the chemotherapeutic agents; in particular low water solubility and low stability, resulting in poor efficacy. Due to their capability to form molecular inclusions with apolar molecules (or part of them) cyclodextrins constitute a powerful tool to prepare more efficient chemotherapeutic delivery systems such as nanoparticles. This review focuses on polymeric nanoparticles for cancer therapy prepared from either cyclodextrin molecules, or polymer and cyclodextrins.
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Dujardin, G., Boer-Duchemin, E., Le Moal, E., Mayne, A. J., & Riedel, D. (2016). DIET (Dynamics at surfaces Induced by Electronic Transitions) at the nanoscale. Surf. Sci., 643, 13–17.
Résumé: We review the long maturing evolution of DIET (Dynamics at surfaces Induced by Electronic Transitions) that began in the 1960s when Menzel, Gomer and Redhead proposed their famous stimulated desorption model. DIET entered the « nanoscale » in the 1990s when researchers at Bell Labs and IBM realized that the Scanning Tunneling Microscope (STM) could be used as an atomic size source of electrons to electronically excite individual atoms and molecules at surfaces. Resonant and radiant Inelastic Electron Tunneling (IET) using the STM have considerably enlarged the range of applications of DIET. Nowadays, « DIET at the nanoscale » covers a broad range of phenomena at the atomic-scale. This includes molecular dynamics (dissociation, desorption, isomerization, displacement, chemical reaction), vibrational spectroscopy and dynamics, spin spectroscopy and manipulation, luminescence spectroscopy, Raman spectroscopy and plasmonics. Future trends of DIET at the nanoscale offer exciting prospects for new methods to control light and matter at the nanoscale.
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Falvo, C. (2016). A new interpretation of the meaning of the center of line slope from a two-dimensional infrared spectrum. JOURNAL OF CHEMICAL PHYSICS, 144(23), 234103.
Résumé: This article presents a new approximation to understand the connection between the center of line slope from a single peak of a two-dimensional (2D) infrared spectrum and the frequency-frequency correlation function. This approximation which goes beyond the short-time approximation includes explicitly pure dephasing mechanisms by introducing a time parameter that separates the fast fluctuations and slow fluctuations. While in the short-time approximation, the center of line slope is given by the normalized frequency fluctuations auto-correlation function, I show using this new approximation that the center of line slope measures on long time scales a shifted and scaled correlation function. The results present a new interpretation of the meaning of the center of line slope that allows for a better understanding of what 2D experiments can measure. To illustrate these findings, I compare this approximation with the short-time approximation for several examples of frequency-frequency correlation functions. I also give an estimate of the value of the time separation parameter for a correlation function with a simple exponential decay.
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Fedortchenko S., Huppert S., Vasanelli A., Todorov Y., Ciuti C., Keller A., Coudreau T., & Milman P. (2016). Output squeezed radiation from dispersive ultrastrong light-matter coupling. Phys. Rev. A, 94, 013821.
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Fensterbank, H., Baczko, K., Constant, C., Idttalbe, N., Bourdreux, F., Vallee, A., Goncalves, A. M., Meallet-Renault, R., Clavier, G., Wright, K., & Allard, E. (2016). Sequential Copper-Catalyzed Alkyne-Azide Cycloaddition and Thiol-Maleimide Addition for the Synthesis of Photo- and/or Electroactive Fullerodendrimers and Cysteine-Functionalized Fullerene Derivatives. Journal Of Organic Chemistry, 81(18), 8222–8233.
Résumé: In this study, the functionalization of a fullerene building block in a stepwise process by means of the copper- catalyzed alkyne azide cycloaddition (CuAAC) and thiol- maleimide reactions is reported. Grafting of the fullerene plat- form with a variety of azido derivatives, including Bodipy, pyrene and ferrocene, was carried out first. These fullerene compounds were then reacted with thiol derivatives to yield sophisticated structures comprising photo- and/or electroactive fullerodendrimers and cysteine-functionalized fullerene assemblies. This strategy, which combines the CuAAC and thiol-maleimide processes, could become more widely adopted in the field of fullerene chemistry.
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Finkelstein-Shapiro, D., Calatayud, M., Atabek, O., Mujica, V., & Keller, A. (2016). Nonlinear Fano interferences in open quantum systems: An exactly solvable model. Physical Review A, 93, 063414.
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Firmino, T., Mangaud, E., Cailliez, F., Devolder, A., Mendive-Tapia, D., Gatti, F., Meier, C., Desouter-Lecomte, M., & de la Lande, A. (2016). Quantum effects in ultrafast electron transfers within cryptochromes. Physical Chemistry Chemical Physics, 18(31), 21442–21457.
Résumé: Cryptochromes and photolyases are flavoproteins that may undergo ultrafast charge separation upon electronic excitation of their flavin cofactors. Charge separation involves chains of three or four tryptophan residues depending on the protein of interest. The molecular mechanisms of these processes are not completely clear. In the present work we investigate the relevance of quantum effects like the occurrence of nuclear tunneling and of coherences upon charge transfer in Arabidopsis thaliana cryptochromes. The possible breakdown of the Condon approximation is also investigated. We have devised a simulation protocol based on the realization of molecular dynamics simulations on diabatic potential energy surfaces defined at the hybrid constrained density functional theory/molecular mechanics level. The outcomes of the simulations are analyzed through various dedicated kinetics schemes related to the Marcus theory that account for the aforementioned quantum effects. MD simulations also provide a basic material to define realistic model Hamiltonians for subsequent quantum dissipative dynamics. To carry out quantum simulations, we have implemented an algorithm based on the Hierarchical Equations of Motion. With this new tool in hand we have been able to model the electron transfer chain considering either two- or three-state models. Kinetic models and quantum simulations converge to the conclusion that quantum effects have a significant impact on the rate of charge separation. Nuclear tunneling involving atoms of the tryptophan redox cofactors as well as of the environment (protein atoms and water molecules) is significant. On the other hand non-Condon effects are negligible in most simulations. Taken together, the results of the present work provide new insights into the molecular mechanisms controlling charge separation in this family of flavoproteins.
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Gans, B., Holzmeier, F., Krüger, J., Falvo, C., Röder, A., Lopes, A., Garcia, G. A., Fittschen, C., Loison, J. - C., & Alcaraz, C. (2016). Synchrotron-based valence shell photoionization of CH radical. JOURNAL OF CHEMICAL PHYSICS, 144(20), 204307.
Résumé: We report the first experimental observations of X+ 1Σ+ ← X 2Π and a+ 3Π ← X 2Π single-photon ionization transitions of the CH radical performed on the DESIRS beamline at the SOLEIL synchro- tron facility. The radical was produced by successive hydrogen-atom abstractions on methane by uorine atoms in a continuous microwave discharge ow tube. Mass-selected ion yields and photo- electron spectra were recorded as a function of photon energy using a double imaging photoelec- tron/photoion coincidence spectrometer. The ion yield appears to be strongly a ected by vibrational and electronic autoionizations, which allow the observation of high Rydberg states of the neutral species. The photoelectron spectra enable the rst direct determinations of the adiabatic ionization potential and the energy of the rst triplet state of the cation with respect to its singlet ground state. This work also brings valuable information on the complex electronic structure of the CH radical and its cation and adds new observations to complement our understanding of Rydberg states and autoionization processes.
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Gans, B., Lamarre, N., Broquier, M., Liévin, J., & Boyé-Péronne, S. (2016). Experimental and ab initio characterisation of HC3N+ vibronic structure: II- High-resolution VUV PFI-ZEKE spectroscopy. JOURNAL OF CHEMICAL PHYSICS, 145, 234309.
Résumé: VUV pulsed-field-ionization zero-kinetic-energy photoelectron spectra of X+ 2Π ←X 1Σ+ and B+ 2Π ← X 1Σ+ transitions of the HC14N and HC15N isotopologues of cyanoacetylene have been recorded. The resolution of the photoelectron spectra allowed to resolve the vibrational structures and the spin-orbit splittings in the
cation. Accurate values of the adiabatic ionization potentials of the two isotopologues (E /hc(HC14N) = 93909(2) cm−1 and E /hc(HC15N) = 93912(2) cm−1), the vibrational frequencies of the ν2, ν6, and ν7 vibrational modes, and the spin-orbit coupling constant (ASO = −44(2) cm−1) of the X+ 2Π cationic ground state have been derived from the measurements. Using ab initio calculations, the unexpected structure of the B+ 2Π ← X 1Σ+ transition is tentatively attributed to a conical intersection between the A+ and B+ electronic states of the cation.
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Gauyacq, J. P., & Lorente, N. (2016). Extremely long-lived magnetic excitations in supported Fe chains. Phys. Rev. B, 94(4), 045420.
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Gavilan, L., Alata, I., Le, K. C., Pino, T., Giuliani, A., & Dartois, E. (2016). VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction. A&A, 586, A106.
Résumé: Context. A full spectral characterization of carbonaceous dust analogs is necessary to understand their potential as carriers of observed astronomical spectral signatures such as the ubiquitous UV bump at 217.5 nm and the far-ultraviolet (FUV) rise common to interstellar extinction curves.
Aims. Our goal is to study the spectral properties of carbonaceous dust analogs from the FUV to the mid-infrared (MIR) domain. We seek in particular to understand the spectra of these materials in the FUV range, for which laboratory studies are scarce.
Methods. We produced analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium: amorphous hydrogenated carbons (a-C:H), for carbonaceous dust observed in the diffuse interstellar medium, and soot particles, for the polyaromatic component. Analogs to a-C:H dust were produced using a radio-frequency plasma reactor at low pressures, and soot nanoparticles films were produced in an ethylene (C2H4) flame. We measured transmission spectra of these thin films (thickness <100 nm) in the far-ultraviolet (190−250 nm) and in the vacuum-ultraviolet (VUV; 50−190 nm) regions using the APEX chamber at the DISCO beam line of the SOLEIL synchrotron radiation facility. These were also characterized through infrared microscopy at the SMIS beam line.
Results. We successfully measured the transmission spectra of these analogs from λ = 1 μm to 50 nm. From these, we extracted the laboratory optical constants via Kramers-Kronig inversion. We used these constants for comparison to existing interstellar extinction curves.
Conclusions. We extend the spectral measurements of these types of carbonaceous analogs into the VUV and link the spectral features in this range to the 3.4 μm band. We suggest that these two materials might contribute to different classes of interstellar extinction curves.
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Grazon, C., Rieger, J., Beaunier, P., Meallet-Renault, R., & Clavier, G. (2016). Fluorescent core-shell nanoparticles and nanocapsules using comb-like macromolecular RAFT agents: synthesis and functionalization thereof. Polymer Chemistry, 7(25), 4272–4283.
Résumé: Fluorescent nanoparticles and nanocapsules (FNPs) were synthesized via a one-pot RAFT miniemulsion process copolymerizing BODIPY-methacrylate and styrene in water. Ultra-bright sub-100 nm core-shell nanoparticles could be obtained with BODIPY covalently linked in the core, and possessing various shells. The nature and architecture of the particle shells could be tuned by using different macromolecular RAFT (macro-RAFT) agents in the miniemulsion polymerization process. The macro-RAFT agents were composed of poly(ethylene oxide) acrylate (PEOA) and/or acrylic acid (AA), owing to their biocompatibility and functionality respectively, in different proportions. Interestingly, with comb-like macro-RAFT agents comprising a high number of PEOA, nanocapsules were formed, while with linear macro-RAFT agents or with those exhibiting a high number of AA, full core-shell nanoparticles were obtained. For all the structures the control over the polymerization, the size, morphology, and zeta-potential as well as the photophysical properties were measured and compared with FNPs exhibiting a linear PEO-b-PAA block copolymer shell structure (C. Grazon, J. Rieger, R. Mallet-Renault, G. Clavier and B. Charleux, Macromol. Rapid Commun., 2011, 32, 699). Regardless of the shell structures, the brightness of the formed nanoparticles was estimated to be 100-1000 times higher than that of quantum dots. Ultimately, the shell of the different FNPs was functionalized with a second fluorophore via the AA's carboxyl groups. Thus, watersoluble ultra-bright FNPs with two fluorophores in distinct environments (water and in polystyrene) were obtained. They should have great potential for bioimaging applications.
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Gruber, E., Wilhelm, R. A., Petuya, R., Smejkal, V., Kozubek, R., Hierzenberger, A., Bayer, B. C., Aldazabal, I., Kazansky, A. K., Libisch, F., Krasheninnikov, A. V., Schleberger, M., Facsko, S., Borisov, A. G., Arnau, A., & Aumayr, F. (2016). Ultrafast electronic response of graphene to a strong and localized electric field. Nat. Commun., 7, 13948.
Résumé: The way conduction electrons respond to ultrafast external perturbations in low dimensional materials is at the core of the design of future devices for (opto)electronics, photodetection and spintronics. Highly charged ions provide a tool for probing the electronic response of solids to extremely strong electric fields localized down to nanometre-sized areas. With ion transmission times in the order of femtoseconds, we can directly probe the local electronic dynamics of an ultrathin foil on this timescale. Here we report on the ability of freestanding single layer graphene to provide tens of electrons for charge neutralization of a slow highly charged ion within a few femtoseconds. With values higher than 10(12) A cm(-2), the resulting local current density in graphene exceeds previously measured breakdown currents by three orders of magnitude. Surprisingly, the passing ion does not tear nanometre-sized holes into the single layer graphene. We use time-dependent density functional theory to gain insight into the multielectron dynamics.
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Gruet, S., Pirali, O., Goubet, M., Tokaryk, D. W., & Bréchignac, P. (2016). High Resolution Far-Infrared Spectroscopy of N-Substituted Two-Ring Polycyclic Aromatic Hydrocarbons: an Extended Study. Journal of Physical Chemistry A, 120(1), 95–105.
Résumé: Polycyclic aromatic hydrocarbons (PAHs) and their N-substituted derivatives are among the largest species for which gas-phase high-resolution spectroscopy can be performed nowadays. In this paper we report the observation and analysis of spectra from several N-substituted two-ring PAHs, all taken in the “fingerprint” far-infrared region (< 850 cm-1). Together with accurate measurements of their pure rotational transitions in the millimeter and sub-millimeter ranges, these synchrotron-based Fourier Transform InfraRed (FTIR) measurements provide an accurate description of the rotational energy levels in the ground and low-energy excited vibrational states of these species. To complement the experimental data, anharmonic DFT calculations were performed to obtain relatively accurate rotational and vibrational parameters. The calculated results strongly support the rotational analysis and provide a good estimate of the equilibrium structures for each species. Extended measurements, analysis and calculations are presented here for the far-IR bands of quinoline (C9H7N), isoquinoline (C9H7N), quinoxaline (C8H6N2), quinazoline (C8H6N2), [1,5]-naphthyridine (C8H6N2), [1,6]-naphthyridine (C8H6N2) and indole (C8H7N) molecules.
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Gutierrez-Quintanilla, A., Chevalier, M., & Crepin, C. (2016). Double deuterated acetylacetone in neon matrices: infrared spectroscopy, photoreactivity and the tunneling process. Phys Chem Chem Phys, 18(30), 20713–20725.
Résumé: The effect of deuteration of acetylacetone (C5O2H8) is explored by means of IR spectroscopy of its single and double deuterated isotopologues trapped in neon matrices. The whole vibrational spectra of chelated enols are very sensitive to the H-D exchange of the hydrogen atom involved in the internal hydrogen bond. UV excitation of double deuterated acetylacetone isolated in neon matrices induces the formation of four open enol isomers which can be divided into two groups of two conformers, depending on their formation kinetics. Within each group, one conformer is more stable than the other: slow conformer interconversion due to a tunneling process is observed in the dark at low temperature. Moreover, IR laser irradiation at the OD stretching overtone frequency is used to induce interconversion either from the most stable to the less stable conformer or the opposite, depending on the excitation wavelength. The interconversion process is of great help to assign conformers which are definitively identified by comparison between experimental and calculated IR spectra. Kinetic constants of the tunneling process at play are theoretically estimated and agree perfectly with experiments, including previous experiments with the totally hydrogenated acetylacetone.
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Hamoudi, H., & Esaulov, V. A. (2016). Selfassembly of α,ω-dithiols on surfaces and metal dithiol heterostructures. Ann.Phys, , 1–22.
Résumé: α,ω-Dithiols present an interesting case of molecules with
two reactive terminal -SH groups (HS-R-SH) that allow their
use as binders between different metallic entities. They have
thus been used in molecular electronics conduction measurements,
in “nanogap” electrodes of interest in plasmonics,
as building blocks of more complex structures such as
metal intercalated superlattices and in the formation of
metalized organic thin films, including doped graphene
type films. There exist however many problems, because
the molecules may end up in undesirable configurations
with both thiol terminals bound to the same metal particle/
substrate or link with other molecules to produce
“multi-molecule” or “multilayer” structures. This report discusses
various key questions on dithiol linking with metal
surfaces and the quest of protocols of making problem free
dithiol metal structures. It then describes the use of dithiols
and their SAMs to produce various metal organic heterostructures
useful for molecular electronics and formation
of doped metalized organic thin films. We discuss the
build up of these structures by self assembly and lithography,
their chemical composition and functional properties.
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Hartmann, J. - M., Landsheere, X., Boulet, C., Sarkisyan, D., Sarkisyan, A. S., Leroy, C., & Pangui, E. (2016). Infrared look at the spectral effects of submicron confinements of CO_2 gas. Physical Review A, 93(1), 012516.
Résumé: We have recorded, near 4.3 μm, transmission spectra of pure CO2 gas inserted between the windows of an extremely thin absorption cell. This was done for three pressures using a Fourier transform spectrometer and five optical paths between 0.17 and 1.15 μm. For these conditions, the line broadening induced by molecule-surface collisions can be studied under “clean” confinement conditions, i.e., between two parallel well-polished crystal surfaces separated by a known distance. This is in opposition with previous investigations using porous materials which involve pores of unknown dimensions with corrugated inner surfaces of ill-defined shapes. The analysis of the spectra shows that the line broadening due to the collisions of the molecules with the cell windows is independent of the optical transition and inversely proportional to the confinement length. Furthermore, the measured values are quantitatively reproduced if one assumes that a single CO2-surface collision is sufficient to interrupt the rotating-dipole coherence. This gives a proof, here for the CO2-sapphire system, of an assumption proposed many years ago and opens promising perspectives for the optical probing of porous materials.
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Izumi, Y., Fujii, K., Wien, F., Houee-Levin, C., Lacombe, S., Salado-Leza, D., Porcel, E., Masoud, R., Yamamoto, S., Refregiers, M., du Penhoat, M. A. H., & Yokoya, A. (2016). Structure Change from beta-Strand and Turn to alpha-Helix in Histone H2A-H2B Induced by DNA Damage Response. Biophysical Journal, 111(1), 69–78.
Résumé: Using synchrotron radiation-based circular dichroism spectroscopy, we found that the DNA damage response induces an increase of alpha-helix structure and a decrease of beta-strand and turn structures in histone H2A-H2B extracted from x-irradiated human HeLa cells. The structural alterations correspond to the assumption that an average of eight amino acid residues form new alpha-helix structures at 310 K. We propose the structural transition from beta-strand and turn structures to an a-helix structure in H2A-H2B as a novel, to our knowledge, process involved in the DNA damage response.
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Jacquinet-Husson, N., Armante, R., Scott, N. A., Chédin, A., Crépeau, L., Boutammine, C., Bouhdaoui, A., Crevoisier, C., Capelle, V., Boonne, C., Poulet-Crovisier, N., Barbe, A., Chris Benner, D., Boudon, V., Brown, L. R., Buldyreva, J., Campargue, A., Coudert, L. H., Devi, V. M., Down, M. J., Drouin, B. J., Fayt, A., Fittschen, C., Flaud, J. - M., Gamache, R. R., Harrison, J. J., Hill, C., Hodnebrog, Ø., Hu, S. - M., Jacquemart, D., Jolly, A., Jiménez, E., Lavrentieva, N. N., Liu, A. - W., Lodi, L., Lyulin, O. M., Massie, S. T., Mikhailenko, S., Müller, H. S. P., Naumenko, O. V., Nikitin, A., Nielsen, C. J., Orphal, J., Perevalov, V. I., Perrin, A., Polovtseva, E., Predoi-Cross, A., Rotger, M., Ruth, A. A., Yu, S. S., Sung, K., Tashkun, S. A., Tennyson, J., Tyuterev, V. G., Vander Auwera, J., Voronin, B. A., & Makie, A. (2016). The 2015 edition of the GEISA spectroscopic database. New Visions of Spectroscopic Databases, Volume II, 327, 31–72.
Résumé: The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974. GEISA is constantly evolving, taking into account the best available spectroscopic data. This paper presents the 2015 release of GEISA (GEISA-2015), which updates the last edition of 2011 and celebrates the 40th anniversary of the database. Significant updates and additions have been implemented in the three following independent databases of GEISA. The “line parameters database” contains 52 molecular species (118 isotopologues) and transitions in the spectral range from 10−6 to 35,877.031 cm−1, representing 5,067,351 entries, against 3,794,297 in GEISA-2011. Among the previously existing molecules, 20 molecular species have been updated. A new molecule (SO3) has been added. HDO, isotopologue of H2O, is now identified as an independent molecular species. Seven new isotopologues have been added to the GEISA-2015 database. The “cross section sub-database” has been enriched by the addition of 43 new molecular species in its infrared part, 4 molecules (ethane, propane, acetone, acetonitrile) are also updated; they represent 3% of the update. A new section is added, in the near-infrared spectral region, involving 7 molecular species: CH3CN, CH3I, CH3O2, H2CO, HO2, HONO, NH3. The “microphysical and optical properties of atmospheric aerosols sub-database” has been updated for the first time since 2003. It contains more than 40 species originating from NCAR and 20 from the ARIA archive of Oxford University. As for the previous versions, this new release of GEISA and associated management software facilities are implemented and freely accessible on the AERIS/ESPRI atmospheric chemistry data center website.
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Jiang, T., Tong, Y., Bendounan, A., Nicolas, F., Kubsky, S., & Esaulov, V. A. (2016). Selenium and benzeneselenol interaction with Cu(111). RSC Adv., 6(88), 84627–84633.
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Kalashnyk N., Khemliche H., & Roncin P. (2016). Atom beam triangulation of organic layers at 100 meV normal energy:self-assembled perylene on Ag(1 1 0) at room temperature. Appl. Surf. Sci., 364, 235–240.
Résumé: The controlled growth of organic layers on surfaces is still waiting for an in-situ reliable technique thatwould allow their quality to be monitored and improved. Here we show that the growth of a perylene monolayer deposited on Ag(110) at room temperature can be tracked with low energy atoms in a regime where the energy perpendicular to the layer is less than 0.1 eV and below the organic film damage threshold. The image processing required for this atom triangulation technique is described in detail.
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Ketterer A., Keller, A., Walborn S. P., Coudreau T., & Milman P. (2016). Quantum information processing in phase space: a modular variables approach. Phys. Rev. A, 94, 022325.
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Kumar, S., Lucas, B., Fayeton, J., Scuderi, D., Alata, I., Broquier, M., Le Barbu-Debus, K., Lepere, V., & Zehnacker, A. (2016). Photofragmentation mechanisms in protonated chiral cinchona alkaloids. Phys. Chem. Chem. Phys., 18(32), 22668–22677.
Résumé: The photo-stability of protonated cinchona alkaloids is studied in the gas phase by a multi-technique approach. A multi-coincidence technique is used to demonstrate that the dissociation is a direct process. Two dissociation channels are observed. They result from the C-8-C-9 cleavage, accompanied or not by hydrogen migration. The branching ratio between the two photo-fragments is different for the two pseudo-enantiomers quinine and quinidine. Mass spectrometry experiments coupling UV photo-dissociation of the reactants and structural characterization of the ionic photo-products by Infra-Red Multiple Photo-Dissociation (IRMPD) spectroscopy provide unambiguous information on their structure. In addition, quantum chemical calculations allow proposing a reactive scheme and discussing it in terms of the ground-state geometry of the reactant.
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Kutzer, P., Weismann, D., Waßmuth, B., Pirali, O., Roy, P., Yamada, K. M. T., & Giesen, T. F. (2016). Far-infrared spectra of dimethyl-ether and its 13C enriched isotopologues: The fundamental band of the C–O–C in plane bending mode, ν7. Journal of Molecular Spectroscopy, 329, 28–34.
Résumé: We recorded the ν 7 fundamental band of dimethyl-ether around 400 cm−1 for the normal and 13C-enriched isotopologues using the Fourier transform spectrometer at the SOLEIL Synchrotron facility. For all three species P, Q and R branch-transitions up to J = 20 and K a = 5 were assigned and the band origins and rotational parameters of Watson’s A-reduced Hamiltonian have been determined by the least-squares fitting procedure. The line splitting due to the torsional tunneling is observed for low J transitions, which is attributed to the ro-vibrational interaction with the excited torsional states.
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Lamarre, N., Gans, B., Vieira Mendes L.A., Gronowski, M., Guillemin, J. - C., de Oliveira N., Douin, S., Chevalier, M., Crépin, C., Kolos, R., & Boyé-Péronne, S. (2016). Excited electronic structure of methylcyanoacetylene probed by VUV Fourier-transform absorption spectroscopy. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 182, 286–295.
Résumé: High resolution photoabsorption spectrum of gas-phase methylcyanoacetylene (CH3C N) has been recorded from 44 500 to 130 000 cm-1 at room temperature with a vacuum ultraviolet Fourier-transform spectrometer on the DESIRS synchrotron beamline (SOLEIL). The absolute photoabsorption cross section in this range is reported for the first time. Valence shell transitions and Rydberg series converging to the ground state X+ 2E of the cation as well as series converging to electronically excited states (A+ 2 A1 and C+) are observed and assigned. Time-dependent density-functional-theory calculations have been performed to support the assignment of the experimental spectrum in the low energy range. A tentative scaling of the previously measured CH3C3N ion yield by Lamarre et al. [17] is proposed, based on the comparison of the absorption data above the first ionization potential with the observed autoionization structures.
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Landsheere, X., Pangui, E., Boulet, C., & Hartmann, J. - M. (2016). Reflection spectroscopy study of the 16O12C16O -band lines. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 174, 1–6.
Résumé: Abstract
Reflection spectra of pure CO2 gas have been recorded in the 4.3 μ m region by using a high resolution Fourier transform spectrometer, providing measured values of the refractive index. Comparisons with the results of calculations using available spectroscopic data, and free of any adjusted line parameter, show a very good agreement. This confirms that this experimental technique provides an alternative approach for the test or determination of spectroscopic parameters. Its advantages for studies of extremely strongly absorbing species and investigations of spatially (tightly) confined molecular gases are discussed.
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Lauzin, C., Gans, B., & Merkt, F. (2016). High-resolution photoelectron-spectroscopic investigation of the H2O+ cation in its A+ electronic state. Molecular Physics, 114(22), 3319–3327.
Résumé: The photoelectron pectrum of water has been recorded in the vicinity of the transition between 112000 and 116000 cm-1 (13.89-14.38 eV). The high resolution allowed the observation of the rotational structure of several bands. Rotational assignments of the transitions involving the Pi(080), Σ(070) and Pi(060) vibronic states of the A+ electronic state are deduced from previous studies of the A+-X+ band system of H2O+ and photoionisation selection rules. The transition to the Σ(030) vibronic state is tentatively assigned.
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Le Marec, A., Guilbaud, O., Larroche, O., & Klisnick, A. (2016). Evidence of partial temporal coherence effects in the linear autocorrelation of extreme ultraviolet laser pulses. Optics Letters, 41(14), 3387–3390.
Résumé: We study how the degree of temporal coherence of plasma-based extreme ultraviolet lasers operated in the amplification of the spontaneous emission mode is encoded in the shape of the linear autocorrelation function, which is obtained from the variation of the fringe visibility while varying the delay in a variable path-difference interferometer. We discuss the implications of this effect when the technique is used to infer the spectral properties of the source. Our numerical simulations, based on a partial coherence model developed by other authors for x-ray free electron lasers, are in good agreement with previously reported sets of measurements, illustrating similar statistical properties for both sources. (C) 2016 Optical Society of America
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Le Moal, E., Marguet, S., Canneson, D., Rogez, B., Boer-Duchemin, E., Dujardin, G., Teperik, T. V., Marinica, D. C., & Borisov, A. G. (2016). Engineering the emission of light from a scanning tunneling microscope using the plasmonic modes of a nanoparticle. Phys. Rev. B, 93(3), 035418.
Résumé: The inelastic tunnel current in the junction formed between the tip of a scanning tunneling microscope (STM) and the sample can electrically generate optical signals. This phenomenon is potentially of great importance for nano-optoelectronic devices. In practice, however, the properties of the emitted light are difficult to control because of the strong influence of the STM tip. In this work, we show both theoretically and experimentally that the sought-after, well-controlled emission of light from an STM tunnel junction may be achieved using a nonplasmonic STM tip and a plasmonic nanoparticle on a transparent substrate. We demonstrate that the native plasmon modes of the nanoparticle may be used to engineer the light emitted in the substrate. Both the angular distribution and intensity of the emitted light may be varied in a predictable way by choosing the excitation position of the STM tip on the particle.
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Leclerc, A., Viennot, D., Jolicard, G., Lefebvre, R., & Atabek, O. (2016). Controlling vibrational cooling with Zero-Width Resonnaces: An adiabatic Floquet approach. Phys. Rev. A, 94, 043409.
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Lefebvre, R. (2016). Factorization and recomposition of molecular wave functions. J Chem Phys, 145(12), 124108.
Résumé: Some situations in the determination of molecular wave functions require to go beyond the Born-Oppenheimer (BO) approximation, with the wave function written as the product of an electronic wave function depending parametrically on the nuclear coordinates and a nuclear wave function. Such situations are usually treated by combining BO products. This form of the wave function leads to coupled equations which determine the nuclear factors of these products. There is another possibility: writing the exact molecular wave function as a single product having formally the same structure as a BO product. This approach has been at the origin of recent developments. We reconsider this problem with the aim of looking at the solutions of the coupled equations which determine the electronic factor of the factorization scheme. It is shown that these coupled equations can be reduced precisely to those encountered with the usual combination of diabatic BO products.
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Lefebvre-Brion, H., & Kalemos, A. (2016). Interpretation of the predissociation of the CO Rydberg W (1)Pi (v = 1) level. J Chem Phys, 144(13), 134302.
Résumé: With the goal to interpret the experimental results obtained quite recently by Heays et al. [J. Chem. Phys. 141, 144311 (2014)] on the predissociation of the Rydberg W (1)Pi (v = 1) vibrational level of the CO molecule, we report herein ab initio potential energy curves of some of its valence and Rydberg states of both (1)Pi and (3)Pi symmetry. Our results confirm that the above vibrational level is perturbed by a new electronic (1)Pi state not observed until now. They correctly reproduce the linewidths of predissociation of the two interacting levels.
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Lefebvre-Brion, H., & Kalemos, A. (2016). Note: Calculation of the branching ratios for the predissociation of the Rydberg CO W(1)Pi(v=1) level. J Chem Phys, 145(16), 166102.
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Lefebvre-Brion, H., Liebermann, H. P., Amero, J. M., & Vazquez, G. J. (2016). Rydberg, valence, and ion-pair quintet states of O2. J Chem Phys, 144(14), 144302.
Résumé: We report an ab initio study of the quintet states of molecular oxygen. The calculations are carried out employing the multireference single and double excitation configuration interaction package. Potential energy curves of the six quintet valence states dissociating into ground state atoms and of the four quintet states dissociating to ion-pair atoms were computed. A number of bound quintet Rydberg series converging to the a(4)Piu and b(4)Sigmag(-) states of the O2(+) cation have been identified.
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Lepere, V., Le Barbu-Debus, K., Clavaguera, C., Scuderi, D., Piani, G., Simon, A. L., Chirot, F., MacAleese, L., Dugourd, P., & Zehnacker, A. (2016). Chirality-dependent structuration of protonated or sodiated polyphenylalanines: IRMPD and ion mobility studies. Phys. Chem. Chem. Phys., 18(3), 1807–1817.
Résumé: Ion mobility experiments are combined with Infra-Red Multiple Photon Dissociation (IRMPD) spectroscopy and quantum chemical calculations for assessing the role of chirality in the structure of protonated and sodiated di- or tetra-peptides. Sodiated systems show a strong chirality dependence of the competition between Na+...O and Na+...pi interactions. Chirality effects are more subtle in protonated systems and manifest themselves by differences in the secondary interactions such hydrogen bonds between neutral groups or those involving the aromatic rings.
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Liu, B. T., Li, H. Y., Xu, X. N., Li, X., Lv, N. N., Singh, V., Stoddart, J. F., York, P., Xu, X., Gref, R., & Zhang, J. W. (2016). Optimized synthesis and crystalline stability of gamma-cyclodextrin metal-organic frameworks for drug adsorption. International Journal Of Pharmaceutics, 514(1), 212–219.
Résumé: The biocompatible and renewable cyclodextrin metal-organic frameworks (CD-MOFs) have addressed a range of opportunities in molecular storage and separation sciences. The reported protocols for their synthesis, however, were carried out at room temperature over long time periods of time (24 h), producing crystals of relatively poor uniformity. In this investigation, micron sized gamma-CD-MOFs were synthesized by an optimized vapor diffusion method at elevated temperature (50 degrees C) within 6 h, after which the size control, crystalline stability and drug adsorption behavior were investigated in detail. In this manner, uniform cubic gamma-CD-MOF crystals were obtained when the reaction temperature was raised to 50 degrees C with pre-addition of the reaction solvent. The size of gamma-CD-MOFs was adjusted efficiently by changing the reactant concentrations, temperatures, time, gamma-CD ratios to KOH and surfactant concentrations, without influencing the porosity and crystallinity of the material markedly. Varing degrees of reduction in crystallinity and change in morphology were observed when the gamma-CD-MOF crystals are treated under conditions of high temperature (100 degrees C), high humidity (92.5%) and polar solvents (e.g., MeOH and DMF). In relation to drug adsorption by gamma-CD-MOFs, most of the drug molecules containing carboxyl groups showed relatively high adsorption (> 5%), while low adsorption (< 5%) was found for drugs with nitrogen-containing heterocyclic rings. In addition, the adsorption kinetics of captopril to standard gamma-CD-MOFs matched a pseudo-second-order model rather well, whilst captopril adsorption to the damaged gamma-CD-MOFs only partially matched the pseudo-second-order model. In summary, based upon the optimized synthesis and size control of gamma-CD-MOFs, the crystalline stability and drug adsorption characteristics of gamma-CD-MOF crystals have been evaluated as a fundamental requirement of a potential vehicle for drug delivery. (C) 2016 Elsevier B.V. All rights reserved.
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Lozada-Garcia, R., Mu, D., Plazanet, M., & Carcabal, P. (2016). Molecular gels in the gas phase? Gelator-gelator and gelator-solvent interactions probed by vibrational spectroscopy. Physical Chemistry Chemical Physics, 18(32), 22100–22107.
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Ma, Q., & Boulet, C. (2016). The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3. JOURNAL OF CHEMICAL PHYSICS, 144(22), 224303.
Résumé: The Robert-Bonamy formalism has been commonly used to calculate half-widths and shifts of spectral lines for decades. This formalism is based on several approximations. Among them, two have not been fully addressed: the isolated line approximation and the neglect of coupling between the translational and internal motions. Recently, we have shown that the isolated line approximation is not necessary in developing semi-classical line shape theories. Based on this progress, we have been able to develop a new formalism that enables not only to reduce uncertainties on calculated half-widths and shifts, but also to model line mixing e ects on spectra starting from the knowledge of the intermolecular potential. In our previous studies, the new formalism had been applied to linear and asymmetric-top molecules. In the present study, the method has been extended to symmetric-top molecules with inversion symmetry. As expected, the inversion splitting induces a complete failure of the isolated line approximation. We have calculated the complex relaxation matrices of self- broadened NH3. The half-widths and shifts in the ν1 and the pure rotational bands are reported in the present paper. When compared with measurements, the calculated half-widths match the experimental data very well, since the inapplicable isolated line approximation has been removed. With respect to the shifts, only qualitative results are obtained and discussed. Calculated o -diagonal elements of the relaxation matrix and a comparison with the observed line mixing e ects are reported in the companion paper (Paper II).
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Margulès, L., Martin-Drumel, M. A., Pirali, O., Bailleux, S., Wlodarczak, G., Roy, P., Roueff, E., & Gerin, M. (2016). Terahertz spectroscopy of the 15NH2 amidogen radical⋆. A&A, 591, A110.
Résumé: Context. The determination of isotopic ratios in interstellar molecules is a powerful probe of chemical routes leading to their formation. In particular, the 14N/15N abundance ratio of nitrogen-bearing species provides information on possible fractionation mechanisms. Up to now there is no accurate determination of this ratio in the interstellar medium (ISM) for the amidogen radical, NH2.
Aims. This work is aimed at determining rotational frequencies of 15NH2 to enable its astronomical detection, which will help to understand the formation mechanisms of nitrogen hydrides in the ISM.
Methods. We performed complementary measurements using both synchrotron-based, broadband far-infrared and high-resolution, submillimeter-wave frequencies to investigate the pure rotational spectrum of the 15NH2 species.
Results. The first spectroscopic study of the 15N-isotopologue of the amidogen radical yielded an accurate set of molecular parameters.
Conclusions. Accurate frequencies are now available for 15NH2 up to 7 THz (with N′′ ≤ 13) allowing dedicated astronomical searches to be undertaken.
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Marinica, D. - C., Aizpurua, J., & Borisov, A. G. (2016). Quantum effects in the plasmon response of bimetallic core-shell nanostructures. Opt. Express, 24(21), 23941–23956.
Résumé: We report a quantum mechanical study of the plasmonic response of bimetallic spherical core/shell nanoparticles. The systems comprise up to 10<sup>4</sup> electrons and their optical response is addressed with Time Dependent Density Functional Theory calculations. These quantum results are compared with classical electromagnetic calculations for core/shell systems formed by Al/Na, Al/Au and Ag/Na, as representative examples of bimetallic systems. We show that for shell widths in the nanometer range, the system cannot be described as a simple stack of two metals. The finite size effect and the transition layer formed between the core and the shell strongly modify the optical properties of the compound nanoparticle. In particular this configuration leads to a frequency shift of the plasmon resonance with shell character and an increased plasmon decay into electron-hole pairs which eventually quenches this resonance for very thin shells. This effect is difficult to capture with a classical theory even upon adjustment of the parameters of a combination of metallic dielectric functions.
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Martin-Drumel, M. A., Roucou, A., Brown, G. G., Thorwirth, S., Pirali, O., Mouret, G., Hindle, F., McCarthy, M. C., & Cuisset, A. . (2016). High resolution spectroscopy of six SOCl2 isotopologues from the microwave to the far-infrared. JOURNAL OF CHEMICAL PHYSICS, 144(8), 084305.
Résumé: Despite its potential role as an atmospheric pollutant, thionyl chloride, SOCl2, remains poorly characterized in the gas phase. In this study, the pure rotational and ro-vibrational spectra of six isotopologues of this molecule, all detected in natural abundance, have been extensively studied from the cm-wave band to the far-infrared region by means of three complementary techniques: chirped-pulse Fourier transform microwave spectroscopy, sub-millimeter-wave spectroscopy using frequency multiplier chain, and synchrotron-based far-infrared spectroscopy. Owing to the complex line pattern which results from two nuclei with non-zero spins, new, high-level quantum-chemical calculations of the hyperfine structure played a crucial role in the spectroscopic analysis. From the combined experimental and theoretical work, an accurate semi-experimental equilibrium structure of SOCl2 has been derived. With the present data, spectroscopy-based methods can now be applied with confidence to detect and monitor this species, either by remote sensing or in situ.
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McLaughlinB. M., Bizau J.-M., Cubaynes D., Guilbaud S., Douix S, Al Shorman M. M., El Ghazaly M. O. A., Sakho I., & Gharaibeh M. F. (2016). K-shell photoionization of O4 + and O5 + ions: experiment and theory. Royal Astronomical Society, 465, 4690.
Résumé: Absolute cross-sections for the K-shell photoionization of Be-like (O4 +) and Li-like (O5 +) atomic oxygen ions were measured for the first time (in their respective K-shell regions) by employing the ion–photon merged-beam technique at the SOLEIL synchrotron-radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/ΔE ≈ 3200 (≈170 meV, full width at half-maximum) was achieved with photon energy from 550 to 670 eV. Rich resonance structure observed in the experimental spectra is analysed using the R-matrix with pseudo-states (RMPS) method. Results are also compared with the screening constant by unit nuclear charge (SCUNC) calculations. We characterize and identify the strong 1s → 2p resonances for both ions and the weaker 1s → np resonances (n ≥ 3) observed in the K-shell spectra of O4 +.
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Milne, C. J., Weber, P. M., Kowalewski, M., Marangos, J. P., Johnson, A. S., Forbes, R., Worner, H. J., Rolles, D., Townsend, D., Schalk, O., Mai, S., Vacher, M., Miller, R. J. D., Centurion, M., Vibok, A., Domcke, W., Cireasa, R., Ueda, K., Bencivenga, F., Neumark, D. M., Stolow, A., Rudenko, A., Kirrander, A., Dowek, D., Martin, F., Ivanov, M., Dahlstrom, J. M., Dudovich, N., Mukamel, S., Sanchez-Gonzalez, A., Minitti, M. P., Austin, D. R., Kimberg, V., & Masin, Z. (2016). Attosecond processes and X-ray spectroscopy: general discussion. Faraday Discussions, 194, 427–462.
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Mosnier, J. P., Kennedy, E. T., van Kampen, P., Cubaynes, D., Guilbaud, S., Sisourat, N., Puglisi, A., Carniato, S., & Bizau, J. M. (2016). Inner-shell photoexcitations as probes of the molecular ions CH+, OH+, and SiH+: Measurements and theory. Physical Review A, 93, 061401.
Résumé: Spectral probes for the CH+, OH+, and SiH+ hydride molecular ions that play key roles in astrophysics and plasma processes are presented. The merged-beam technique at the SOLEIL synchrotron was used to record the photoionization (ion yield) spectra of CH+, OH+, and SiH+ and that of their parent atomic ions, in the K-shell and L-shell regions, respectively. Energies and oscillator strengths for the K alpha (CH+ and OH+) and La (SiH+) transitions were determined from the spectra. Ab initio calculations interpret the experimental data in terms of contributions from ground and excited valence electronic states.
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Orr-Ewing, A. J., Verlet, J. R. R., Penfold, T. J., Minns, R. S., Minitti, M. P., Solling, T. I., Schalk, O., Kowalewski, M., Marangos, J. P., Robb, M. A., Johnson, A. S., Worner, H. J., Shalashilin, D. V., Miller, R. J. D., Domcke, W., Ueda, K., Weber, P. M., Cireasa, R., Vacher, M., Roberts, G. M., Decleva, P., Bencivenga, F., Neumark, D. M., Gessner, O., Stolow, A., Mishra, P. K., Polyak, I., Baeck, K. K., Kirrander, A., Dowek, D., Jimenez-Galan, A., Martin, F., Mukamel, S., Sekikawa, T., Gelin, M. F., Townsend, D., Makhov, D. V., & Neville, S. P. (2016). Electronic and non-adiabatic dynamics: general discussion. Faraday Discussions, 194, 209–257.
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Pearson, J. C., Yu S., & Pirali O. (2016). Modeling the spectrum of the 2 nu(2) and nu(4) states of ammonia to experimental accuracy. JOURNAL OF CHEMICAL PHYSICS, 145(12), 124301.
Résumé: The vibrational spectrum of ammonia has received an enormous amount of attention due to its potential prevalence in hot exo-planet atmospheres and persistent challenges in assigning and modeling highly excited and often highly perturbed states. Effective Hamiltonian models face challenges due to strong coupling between the large amplitude inversion and the other small amplitude vibrations. To date, only the ground and ν2 positions could be modeled to experimental accuracy using effective Hamiltonians. Several previous attempts to analyze the 2ν2 and ν4 energy levels failed to model both the microwave and infrared transitions to experimental accuracy. In this work, we performed extensive experimental measurements and data analysis for the 2ν2 and ν4 inversion-rotation and vibrational transitions. We measured 159 new transition frequencies with microwave precision and assigned 1680 new ones from existing Fourier transform spectra recorded in Synchrotron SOLEIL. The newly assigned data significantly expand the range of assigned quantum numbers; combined with all the previously published high-resolution data, the 2ν2 and ν4 states are reproduced to experimental accuracy using a global model described here. Achieving experimental accuracy required inclusion of a number of terms in the effective Hamiltonian that were neglected in previous work. These terms have also been neglected in the analysis of states higher than 2ν2 and ν4 suggesting that the inversion-rotation-vibration spectrum of ammonia may be far more tractable to effective Hamiltonians than previously believed.
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Pino, G. A., Feraud, G., Broquier, M., Gregoire, G., Soorkia, S., Dedonder, C., & Jouvet, C. (2016). Non-radiative processes in protonated diazines, pyrimidine bases and an aromatic azine. Phys. Chem. Chem. Phys., 18(30), 20126–20134.
Résumé: The excited state lifetimes of DNA bases are often very short due to very efficient non-radiative processes assigned to the pipi*-npi* coupling. A set of protonated aromatic diazine molecules (pyridazine, pyrimidine and pyrazine C4H5N2+) and protonated pyrimidine DNA bases (cytosine, uracil and thymine), as well as the protonated pyridine (C5H6N+), have been investigated. For all these molecules except one tautomer of protonated uracil (enol-keto), electronic spectroscopy exhibits vibrational line broadening. Excited state geometry optimization at the CC2 level has been conducted to find out whether the excited state lifetimes measured from line broadening can be correlated to the calculated ordering of the pipi* and npi* states and the pipi*-npi* energy gap. The short lifetimes, observed when one nitrogen atom of the ring is not protonated, can be rationalized by relaxation of the pipi* state to the npi* state or directly to the electronic ground state through ring puckering.
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Poumellec, B., Lancry, M., Desmarchelier, R., Hervé, E., & Bourguignon, B. (2016). Parity violation in chiral structure creation under femtosecond laser irradiation in silica glass? Light. Sci. Appl., 5(11), e16178.
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Puthumpally-Joseph, R., Sukharev, M., & Charron, E. (2016). Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields. J. Chem. Phys., 144(15), 154109.
Résumé: We introduce a non-Hermitian Schrodinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.
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Puthumpally-Joseph, R., Viau-Trudel, J., Peters, M., Nguyen-Dang, T. T., Atabek, O., & Charron, E. (2016). Inversion of strong-field photoelectron spectra for molecular orbital imaging. Phys. Rev. A, 94(2), 023421.
Résumé: Imaging structures at the molecular level is a developing interdisciplinary research field that spans the boundaries of physics and chemistry. High-spatial-resolution images of molecules can be obtained with photons or ultrafast electrons. In addition, images of valence molecular orbitals can be extracted via tomographic techniques based on the coherent extreme UV radiation emitted by a molecular gas exposed to an intense ultrashort infrared laser pulse. In this paper, we demonstrate that similar information can be obtained by inverting energy-resolved photoelectron spectra using a simplified analytical model.
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Revest, M., Jacqueline, C., Boudjemaa, R., Caillon, J., Le Mabecque, V., Breteche, A., Steenkeste, K., Tattevin, P., Potel, G., Michelet, C., Fontaine-Aupart, M. P., & Boutoille, D. (2016). New in vitro and in vivo models to evaluate antibiotic efficacy in Staphylococcus aureus prosthetic vascular graft infection. Journal Of Antimicrobial Chemotherapy, 71(5), 1291–1299.
Résumé: Prosthetic vascular graft infection (PVGI) is an emerging disease, mostly caused by staphylococci, with limited data regarding efficacy of current antistaphylococcal agents. We aimed to assess the efficacy of different antibiotic regimens. Six different strains of MSSA and MRSA were used. We compared results of minimal biofilm inhibitory and eradicating concentrations (MBICs and MBECs) obtained with a Calgary Biofilm Pin Lid Device (CBPD) with those yielded by an original Dacron (R)-related minimal inhibitory and eradicating concentration measure model. We then used a murine model of Staphylococcus aureus vascular prosthetic material infection to evaluate efficacy of different antibiotic regimens: vancomycin and daptomycin combined or not with rifampicin for MRSA and the same groups with cloxacillin and cloxacillin combined with rifampicin for MSSA. We demonstrated that classical measures of MBICs and MBECs obtained with a CPBD could overestimate the decrease in antibiotic susceptibility in material-related infections and that the nature of the support used might influence the measure of biofilm susceptibility, since results yielded by our Dacron (R)-related minimal eradicating assay were lower than those found with a plastic device. In our in vivo model, we showed that daptomycin was significantly more bactericidal than comparators for some strains of MRSA or MSSA but not for all. For the majority of strains, it was as efficient as comparators. The addition of rifampicin to daptomycin did not enhance daptomycin efficacy. Despite the heterogeneity of results according to bacterial strains, these innovative models represent an option to better evaluate the in vitro efficacy of antibiotics on Dacron (R)-related biofilm S. aureus infections, and to screen different antibiotic regimens in a mouse model of PVGIs.
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Rogez, B., Cao, S., Dujardin, G., Comtet, G., Le Moal, E., Mayne, A. J., & Boer-Duchemin, E. (2016). The mechanism of light emission from a scanning tunnelling microscope operating in air. Nanotechnology, 27(46), 465201.
Résumé: The scanning tunnelling microscope (STM) may be used as a low-energy, electrical nanosource of surface plasmon polaritons and light. In this article, we demonstrate that the optimum mode of operation of the STM for maximum photon emission is completely different in air than in vacuum. To this end, we investigate the emission of photons, the variation in the relative tip-sample distance and the measured current as a function of time for an STM operating in air. Contrary to the case of an STM operating in vacuum, the measured current between the tip and sample for an STM in air is very unstable (rapidly fluctuating in time) when the applied voltage between the tip and sample is in the ∼1.5–3 V range (i.e., in the energy range of visible photons). The photon emission occurs in short (50 μs) bursts when the STM tip is closest to the sample. The current instabilities are shown to be a key ingredient for producing intense light emission from an STM operating in air (photon emission rate several orders of magnitude higher than for stable current). These results are explained in terms of the interplay between the tunnel current and the electrochemical current in the ubiquitous thin water layer that exists when working in air.
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Saideh V., Felicetti S., Coudreau T., Milman P., & Keller A. (2016). Generalized spin-squeezing inequalities for particle number with quantum fluctuations. Phys. Rev. A, 94, 032312.
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Schlatholter, T., Eustache, P., Porcel, E., Salado, D., Stefancikova, L., Tillement, O., Lux, F., Mowat, P., Biegun, A. K., van Goethem, M. J., Remita, H., & Lacombe, S. (2016). Improving proton therapy by metal-containing nanoparticles: nanoscale insights. International Journal Of Nanomedicine, 11, 1549–1556.
Résumé: The use of nanoparticles to enhance the effect of radiation-based cancer treatments is a growing field of study and recently, even nanoparticle-induced improvement of proton therapy performance has been investigated. Aiming at a clinical implementation of this approach, it is essential to characterize the mechanisms underlying the synergistic effects of nanoparticles combined with proton irradiation. In this study, we investigated the effect of platinum- and gadolinium-based nanoparticles on the nanoscale damage induced by a proton beam of therapeutically relevant energy (150 MeV) using plasmid DNA molecular probe. Two conditions of irradiation (0.44 and 3.6 keV/mu m) were considered to mimic the beam properties at the entrance and at the end of the proton track. We demonstrate that the two metal-containing nanoparticles amplify, in particular, the induction of nanosize damages (>2 nm) which are most lethal for cells. More importantly, this effect is even more pronounced at the end of the proton track. This work gives a new insight into the underlying mechanisms on the nanoscale and indicates that the addition of metal-based nanoparticles is a promising strategy not only to increase the cell killing action of fast protons, but also to improve tumor targeting.
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Schubert, A., Falvo, C., & Meier, C. (2016). Mixed quantum-classical simulations of the vibrational relaxation of photolyzed carbon monoxide in a hemoprotein. JOURNAL OF CHEMICAL PHYSICS, 145(5), 054108.
Résumé: We present mixed quantum-classical simulations on relaxation and dephasing of vibrationally excited carbon monoxide within a protein environment. The methodology is based on a vibrational surface hopping approach treating the vibrational states of CO quantum mechanically, while all remaining degrees of freedom are described by means of classical molecular dynamics. The CO vibrational states form the “surfaces” for the classical trajectories of protein and solvent atoms. In return, environmentally induced non-adiabatic couplings between these states cause transitions describing the vibrational relaxation from first principles. The molecular dynamics simulation yields a detailed atomistic picture of the energy relaxation pathways, taking the molecular structure and dynamics of the protein and its solvent fully into account. Using the ultrafast photolysis of CO in the hemoprotein FixL as an example, we study the relaxation of vibrationally excited CO and evaluate the role of each of the FixL residues forming the heme pocket.
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Si, Y., Grazon, C., Clavier, G., Rieger, J., Audibert, J. F., Sclavi, B., & Meallet-Renault, R. (2016). Rapid and accurate detection of Escherichia coli growth by fluorescent pH-sensitive organic nanoparticles for high-throughput screening applications. Biosensors & Bioelectronics, 75, 320–327.
Résumé: Rapid detection of bacterial growth is an important issue in the food industry and for medical research. Here we present a novel kind of pH-sensitive fluorescent nanoparticles (FANPs) that can be used for the rapid and accurate real-time detection of Escherichia coil growth. These organic particles are designed to be non-toxic and highly water-soluble. Here we show that the coupling of pH sensitive fluoresceinamine to the nanoparticles results in an increased sensitivity to changes in pH within a physiologically relevant range that can be used to monitor the presence of live bacteria. In addition, these FANPs do not influence bacterial growth and are stable over several hours in a complex medium and in the presence of bacteria. The use of these FANPs allows for continuous monitoring of bacterial growth via real-time detection over long time scales in small volumes and can thus be used for the screening of a large number of samples for high-throughput applications such as screening for the presence of antibiotic resistant strains. (C) 2015 Elsevier B.V. All rights reserved.
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Simon-Yarza, M. T., Baati, T., Paci, A., Lesueur, L. L., Seck, A., Chiper, M., Gref, R., Serre, C., Couvreur, P., & Horcajada, P. (2016). Antineoplastic busulfan encapsulated in a metal organic framework nanocarrier: first in vivo results. Journal Of Materials Chemistry B, 4(4), 585–588.
Résumé: Nanoparticles of a mesoporous iron(III) trimesate MIL-100 nanocarrier encapsulating high amounts of the challenging antineoplastic busulfan were administered to rats and compared with the commercial Busilvex (R). Large differences in serum concentration of both busulfan and trimesate revealed the great impact of drug encapsulation both on the drug and on nanoparticle pharmacokinetics during the first 24 h of administration.
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Simon-Yarza, T., Baati, T., Neffati, F., Njim, L., Couvreur, P., Serre, C., Gref, R., Najjar, M. F., Zakhama, A., & Horcajada, P. (2016). In vivo behavior of MIL-100 nanoparticles at early times after intravenous administration. International Journal Of Pharmaceutics, 511(2), 1042–1047.
Résumé: Metal-organic frameworks have shown interesting features for biomedical applications, such as drug delivery and imaging agents. The benchmarked mesoporous iron(III) trimesate MIL-100 MOF nanocarrier combines progressive release of high drug cargoes with absence of visible in vivo toxicity. Although in a previous study pharmacokinetics and biodistribution of MIL-100 nanoparticles were evaluated in the long term (from 24h to 1 month), the crucial times for drug targeting and delivery applications are shorter (up to 24 h). Thus, this work aims to study the blood circulating profile and organ accumulation of MIL-100 nanocarrier at early times after administration. For this purpose, after intravenous administration to rats, both constitutive components of MIL-100 (trimesate and iron) were quantified by high performance liquid chromatography and a spectrophotometric method, respectively. The pharmacokinetic profile suggested that the nanoparticles act as a depot in the blood stream during the first hours before being cleared. Accumulation took mainly place in the liver and, in some extent, in the spleen. Nevertheless, histological studies demonstrated the absence of morphological alterations due to the presence of the particles in these organs. Liver function was however slightly altered as reflected by the increased plasma aspartate aminotransferase concentrations. Finally trimesate was progressively eliminated in urine. (C) 2016 Elsevier B.V. All rights reserved.
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Sonnet, P., Stauffer, L., Gille, M., Bléger, D., Hecht, S., Cejas, C., Dujardin, G., & Mayne, A. J. (2016). Molecular dissociation on the SiC(0001)-3x3 surface. ChemPhysChem, 17(23), 3900–3906.
Résumé: In the framework of density functional theory, the adsorption of the halogenated polycyclic aromatic hydrocarbon 2,11-diiodohexabenzocoronene (HBC-I2) on the SiC(0001) 3×3 surface has been investigated. Nondissociative and dissociative molecular adsorption is considered, and simulated scanning tunneling microscopy (STM) images are compared with the corresponding experimental observations. Calculations show that dissociative adsorption is favorable and reveal the crucial importance of the extended flat carbon core on molecule–surface interactions in dissociative adsorption; the iodine atom–surface interaction is of minor importance. Indeed, removing iodine atoms does not significantly affect the STM images of the central part of the molecule. This study shows that the dissociation of large halogenated polycyclic aromatic hydrocarbon molecules can occur on the SiC surface. This opens up interesting perspectives in the chemical reactivity and functionalization of wide band gap semiconductors.
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Soorkia, S., Broquier, M., & Gregoire, G. (2016). Multiscale excited state lifetimes of protonated dimethyl aminopyridines. Phys. Chem. Chem. Phys., 18(34), 23785–23794.
Résumé: The excited state dynamics of protonated ortho (2-) and para (4-) dimethyl aminopyridine molecules (DMAPH(+)) has been studied through pump-probe photofragmentation spectroscopy and excited state coupled-cluster CC2 calculations. Multiscale temporal dynamics has been recorded over 9 orders of magnitude from subpicosecond to millisecond. The initially locally excited pipi* state rapidly decays within about 100 fs into a charge transfer state following 90 degrees twist motion of the dimethyl amino group. While this twisted intramolecular charge transfer (TICT) state does not trigger any fragmentation, it selectively leads to specific two-color photofragments through absorption of the probe photon at 355 nm. Besides, the optically dark TICT state provides an efficient deactivation path with high intersystem probability to non-dissociative long-lived triplet states. Such a multiscale pump-probe photodissociation scheme paves the way to systematic studies of charge transfer reactions in the excited state of cold ionic systems stored in a cryogenic cooled ion trap and probed continuously up to the millisecond time scale.
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Stefancikova, L., Lacombe, S., Salado, D., Porcel, E., Pagacova, E., Tillement, O., Lux, F., Depes, D., Kozubek, S., & Falk, M. (2016). Effect of gadolinium-based nanoparticles on nuclear DNA damage and repair in glioblastoma tumor cells. Journal Of Nanobiotechnology, 14.
Résumé: Background: Tumor targeting of radiotherapy represents a great challenge. The addition of multimodal nanoparticles, such as 3 nm gadolinium-based nanoparticles (GdBNs), has been proposed as a promising strategy to amplify the effects of radiation in tumors and improve diagnostics using the same agents. This singular property named theranostic is a unique advantage of GdBNs. It has been established that the amplification of radiation effects by GdBNs appears due to fast electronic processes. However, the influence of these nanoparticles on cells is not yet understood. In particular, it remains dubious how nanoparticles activated by ionizing radiation interact with cells and their constituents. A crucial question remains open of whether damage to the nucleus is necessary for the radiosensitization exerted by GdBNs (and other nanoparticles). Methods: We studied the effect of GdBNs on the induction and repair of DNA double-strand breaks (DSBs) in the nuclear DNA of U87 tumor cells irradiated with.-rays. For this purpose, we used currently the most sensitive method of DSBs detection based on high-resolution confocal fluorescence microscopy coupled with immunodetection of two independent DSBs markers. Results: We show that, in the conditions where GdBNs amplify radiation effects, they remain localized in the cytoplasm, i.e. do not penetrate into the nucleus. In addition, the presence of GdBNs in the cytoplasm neither increases induction of DSBs by.-rays in the nuclear DNA nor affects their consequent repair. Conclusions: Our results suggest that the radiosensitization mediated by GdBNs is a cytoplasmic event that is independent of the nuclear DNA breakage, a phenomenon commonly accepted as the explanation of biological radiation effects. Considering our earlier recognized colocalization of GdBNs with the lysosomes and endosomes, we revolutionary hypothesize here about these organelles as potential targets for (some) nanoparticles. If confirmed, this finding of cytoplasmically determined radiosensitization opens new perspectives of using nano-radioenhancers to improve radiotherapy without escalating the risk of pathologies related to genetic damage.
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Sung, K., Yu, S., Pearson, J., Pirali, O., Kwabia Tchana, F., & Manceron, L. (2016). Far-infrared 14NH3 line positions and intensities measured with a FT-IR and AILES beamline, Synchrotron SOLEIL. New Visions of Spectroscopic Databases, Volume II, 327, 1–20.
Résumé: Abstract
Extensive measurements of line positions and intensities are reported for the inversion-rotation and rovibrational transitions of 14NH3 in the 50–660 cm−1 region. This study analyzes high-resolution (0.00167 cm−1, unapodized) Fourier-transform spectra of high purity (99.5%) normal ammonia sample obtained using the AILES beamline of Synchrotron SOLEIL. The experimental conditions are designed to study transitions with intensities weaker than 1 × 10−22 cm−1/(molecule cm−2) at room temperature. Line positions and intensities of more than 2830 transitions of 14NH3 are measured and compiled after proper quality control; the features from minor isotopologues (15NH3 and NH2D) and H2O are identified and excluded. Based on the predictions of recent work from the empirical Hamiltonian modeling, systematic quantum assignments are made for 2047 transitions from eight bands including four inversion-rotation (gs, v2, 2v2, and v4) and four ro-vibrational bands (v2–gs, 2v2–v2, v4–v2, and 2v2–v4), as well as covering their ΔK = 3 forbidden transitions. The measured line positions for the assigned transitions are in an excellent agreement (typically better than 0.001 cm−1) with the predictions in a wide range of J and K for all the eight bands. The comparison with the HITRAN 2012 database is also satisfactory, although systematic offsets are seen for transitions with high J and K and those from weak bands. Also we note that out of the eight bands, the 2v2–v4 has not been listed in the HITRAN 2012 database. Differences of 20% are seen between our measured and calculated intensities depending on the bands. For line positions, greater differences are found for some NH3 bands in HITRAN 2012 than recent predictions. Measurements of the individual line positions and intensities are presented for the eight bands, and the final spectroscopic line positions and intensities are compiled as an electronic supplement.
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Teperik, T. V., Kazansky, A. K., & Borisov, A. G. (2016). Electron tunneling through water layer in nanogaps probed by plasmon resonances. Phys. Rev. B, 93(15), 155431.
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Thon, R., Chin, W., Chamma, D., Galaup, J. - P., Ouvrard, A., Bourguignon, B., & Crépin, C. (2016). Vibrational spectroscopy and dynamics of W(CO)6in solid methane as a probe of lattice properties. J. Chem. Phys., 145(21), 214306.
Résumé: Methane solids present more than one accessible crystalline phase at low temperature at zero pressure. We trap W(CO)6 in CH4 and CD4 matrices between 8 and 35 K to probe the interaction between an impurity and its surrounding molecular solid under various physical conditions. Linear and nonlinear vibrational spectroscopies of W(CO)6 highlight different kinds of interaction and reveal new and remarkable signatures of the phase transition of methane. The structures in the absorption band of the antisymmetric CO stretching mode exhibit a clear modification at the transition between phase II and phase I in CH4 and motional narrowing is observed upon temperature increase. The vibrational dynamics of this mode is probed in stimulated photon echo experiments performed with a femtosecond IR laser. A short component around 10 ps is detected in the population relaxation lifetime in the high temperature phase of solid CH4 (phase I) and disappears at lower temperatures (phase II) where the vibrational lifetime is in the hundreds of ps. The analysis of the nonlinear time-resolved results suggests that the short component comes from a fast energy transfer between the vibrational excitation of the guest and the lattice in specific families of sites. Such fast transfers are observed in the case of W(CO)6 trapped in CD4 because of an energy overlap of the excitation of W(CO)6 and a lattice vibron. In solid CH4, even when these V-V transfers are not efficient, pure dephasing processes due to the molecular nature of the host occur: they are temperature dependent without a clear modification at the phase transition.
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Thorwirth, S., Martin-Drumel, M. A., Endres, C. P., Salomon, T., Zingsheim, O., van Wijngaarden, J., Pirali, O., Gruet, S., Lewen, F., Schlemmer, S., & McCarthy, M. C. (2016). An ASAP treatment of vibrationally excited S2O: The ν3 mode and the ν3 + ν2 − ν2 hot band. Journal of Molecular Spectroscopy, 319, 47–49.
Résumé: Abstract
The fundamental S–S stretching mode ν3 of disulfur monoxide, S2O, located at 679 cm−1, has been investigated using Fourier-transform far-infrared spectroscopy at the SOLEIL synchrotron facility. A spectroscopic analysis has been performed using an Automated Spectral Assignment Procedure (ASAP) which permits accurate determination of more than 2000 energy levels from ν3. In addition, the ν3 + ν2 − ν2 hot band was observed for the first time and some 500 corresponding energy levels were assigned. The high-resolution synchrotron study was complemented with pure rotational spectra of S2O in the (v1, v2, v3) = (0, 0, 1) vibrational state observed in the frequency range from 250 to 280 GHz using a long-path absorption cell. From these combined measurements, extensive molecular parameter sets have been determined and precise band centers have been derived for both vibrational bands.
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Tong, Y., Jiang, T., Bendounan, A., Harish, M. N. K., Giglia, A., Kubsky, S., Sirotti, F., Pasquali, L., Sampath, S., & Esaulov, V. A. (2016). Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes. Beilstein J Nanotechnol, 7, 263–277.
Résumé: This report examines the assembly of chalcogenide organic molecules on various surfaces, focusing on cases when chemisorption is accompanied by carbon-chalcogen atom-bond scission. In the case of alkane and benzyl chalcogenides, this induces formation of a chalcogenized interface layer. This process can occur during the initial stages of adsorption and then, after passivation of the surface, molecular adsorption can proceed. The characteristics of the chalcogenized interface layer can be significantly different from the metal layer and can affect various properties such as electron conduction. For chalcogenophenes, the carbon-chalcogen atom-bond breaking can lead to opening of the ring and adsorption of an alkene chalcogenide. Such a disruption of the pi-electron system affects charge transport along the chains. Awareness about these effects is of importance from the point of view of molecular electronics. We discuss some recent studies based on X-ray photoelectron spectroscopy that shed light on these aspects for a series of such organic molecules.
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Tong, Y., Jiang, T., Bendounan, A., Nicolas, F., Kubsky, S., & Esaulov, V. A. (2016). Selenium, Benzeneselenol, and Selenophene Interaction with Cu(100). J. Phys. Chem. C, 120(38), 21486–21495.
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Valdés, J. E., Vargas, P., & Esaulov, V. A. (2016). Energy losses of slow ions traveling through crystalline solids and scattered on crystalline surfaces. Radiation Effects and Defects in Solids, 171(1-2), 60–76.
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Vander Auwera, J., Boulet, C., Carré, Y., Kocon, L., & Hartmann, J. - M. (2016). Confinement-induced infrared absorption by H2 and N2 gases in a porous silica aerogel. JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, 182, 193–198.
Résumé: Abstract
Transmission spectra in the fundamental bands of H2 and N2 gas inside the pores of a silica aerogel sample were recorded at room temperature and for several pressures using a Fourier transform spectrometer. They first show that, as the absorption is proportional to the pressure, it is due to the interactions of the molecules with the inner surfaces of the pores and not to the dipole induced during gas-phase molecule–molecule collisions. Furthermore, the analysis of the widths and areas of the observed absorption structures indicate that, for the considered aerogel sample, most of the absorption is likely due to “free” molecules moving within the pores with a weak contribution of adsorbed molecules.
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Veyrinas, K., Gruson, V., Weber, S. J., Barreau, L., Ruchon, T., Hergott, J. - F., Houver, J. - C., Lucchese, R. R., Salieres, P., & Dowek, D. (2016). Molecular frame photoemission by a comb of elliptical high-order harmonics: a sensitive probe of both photodynamics and harmonic complete polarization state. Faraday Discussions, 194, 161–183.
Résumé: Due to the intimate anisotropic interaction between an XUV light field and a molecule resulting in photoionization (PI), molecular frame photoelectron angular distributions (MFPADs) are most sensitive probes of both electronic/nuclear dynamics and the polarization state of the ionizing light field. Consequently, they encode the complex dipole matrix elements describing the dynamics of the PI transition, as well as the three normalized Stokes parameters s(1), s(2), s(3) characterizing the complete polarization state of the light, operating as molecular polarimetry. The remarkable development of advanced light sources delivering attosecond XUV pulses opens the perspective to visualize the primary steps of photochemical dynamics in time-resolved studies, at the natural attosecond to few femtosecond time-scales of electron dynamics and fast nuclear motion. It is thus timely to investigate the feasibility of measurement of MFPADs when PI is induced e.g., by an attosecond pulse train (APT) corresponding to a comb of discrete high-order harmonics. In the work presented here, we report MFPAD studies based on coincident electron-ion 3D momentum imaging in the context of ultrafast molecular dynamics investigated at the PLFA facility (CEA-SLIC), with two perspectives: (i) using APTs generated in atoms/molecules as a source for MFPAD-resolved PI studies, and (ii) taking advantage of molecular polarimetry to perform a complete polarization analysis of the harmonic emission of molecules, a major challenge of high harmonic spectroscopy. Recent results illustrating both aspects are reported for APTs generated in unaligned SF6 molecules by an elliptically polarized infrared driving field. The observed fingerprints of the elliptically polarized harmonics include the first direct determination of the complete s(1), s(2), s(3) Stokes vector, equivalent to (psi, epsilon, P), the orientation and the signed ellipticity of the polarization ellipse, and the degree of polarization P. They are compared to so far incomplete results of XUV optical polarimetry. We finally discuss the comparison between the outcomes of photoionization and high harmonic spectroscopy for the description of molecular photodynamics.
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Vu, T. T., Meallet-Renault, R., Clavier, G., Trofimov, B. A., & Kuimova, M. K. (2016). Tuning BODIPY molecular rotors into the red: sensitivity to viscosity vs. temperature. Journal Of Materials Chemistry C, 4(14), 2828–2833.
Résumé: Viscosity variations in the microscopic world are of paramount importance for diffusion and reactions. In the last decade a new class of fluorescent probes for measuring viscosity has emerged termed 'molecular rotors', which allows quantitative mapping of viscosity in microscopically heterogeneous environments. Here we attempt to tune the absorption and emission of one such 'molecular rotor' based on the BODIPY fluorescent core into the red region of the spectrum, to allow better compatibility with the 'tissue optical window' and imaging of cells and tissues. We consequently find that our redemitting BODIPY fluorophores are sensitive to environmental temperature rather than to viscosity, thus suggesting a new prototype for a 'molecular thermometer'.
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Wei, F., Xia, W. -xiu, Hu, Z. -jin, Li, W. -hui, Zhang, J. -ying, & Zheng, W. -quan. (2016). Laser Linewidth and Spectral Resolution in Infrared Scanning Sum Frequency Generation Vibrational Spectroscopy System. Chinese Journal of Chemical Physics, 29(2), 171–178.
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Xian, Z., Liu, R., Li, H., Zhang, S., Yang, Z., Zheng, W., Chen, C., Cao, H., & Zhang, G. (2016). Photocatalytic Reduction Synthesis of Ternary Ag Nanoparticles/Polyoxometalate/Graphene Nanohybrids and Its Activity in the Electrocatalysis of Oxygen Reduction. J Clust Sci, 27(1), 241–256.
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Xiao, X., Wenjun, W., Shuhong, L., Wanquan, Z., Dong, Z., Qianqian, D., Xuexi, G., & Bingyuan, Z. (2016). Investigation of defect modes with Al2O3 and TiO2 in one-dimensional photonic crystals. Optik – International Journal for Light and Electron Optics, 127(1), 135–138.
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Zapata Herrera, M., Aizpurua, J., Kazansky, A. K., & Borisov, A. G. (2016). Plasmon Response and Electron Dynamics in Charged Metallic Nanoparticles. Langmuir, 32(11), 2829–2840.
Résumé: Using the time-dependent density functional theory, we perform quantum calculations of the electron dynamics in small charged metallic nanoparticles (clusters) of spherical geometry. We show that the excess charge is accumulated at the surface of the nanoparticle within a narrow layer given by the typical screening distance of the electronic system. As a consequence, for nanoparticles in vacuum, the dipolar plasmon mode displays only a small frequency shift upon charging. We obtain a blue shift for positively charged clusters and a red shift for negatively charged clusters, consistent with the change of the electron spill-out from the nanoparticle boundaries. For negatively charged clusters, the Fermi level is eventually promoted above the vacuum level leading to the decay of the excess charge via resonant electron transfer into the continuum. We show that, depending on the charge, the process of electron loss can be very fast, on the femtosecond time scale. Our results are of great relevance to correctly interpret the optical response of the nanoparticles obtained in electrochemistry, and demonstrate that the measured shift of the plasmon resonances upon charging of nanoparticles cannot be explained without account for the surface chemistry and the dielectric environment.
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Zhao, Z. Q., Chen, J., Zhang, Z. J., Zhang, D. H., Lauvergnat, D., & Gatti, F. (2016). Full-dimensional vibrational calculations of five-atom molecules using a combination of Radau and Jacobi coordinates: Applications to methane and fluoromethane. JOURNAL OF CHEMICAL PHYSICS, 144(20), 204302.
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Zhu, W., Esteban, R., Borisov, A. G., Baumberg, J. J., Nordlander, P., Lezec, H. J., Aizpurua, J., & Crozier, K. B. (2016). Quantum mechanical effects in plasmonic structures with subnanometre gaps. Nat. Commun., 7, 11495.
Résumé: Metallic structures with nanogap features have proven highly effective as building blocks for plasmonic systems, as they can provide a wide tuning range of operating frequencies and large near-field enhancements. Recent work has shown that quantum mechanical effects such as electron tunnelling and nonlocal screening become important as the gap distances approach the subnanometre length-scale. Such quantum effects challenge the classical picture of nanogap plasmons and have stimulated a number of theoretical and experimental studies. This review outlines the findings of many groups into quantum mechanical effects in nanogap plasmons, and discusses outstanding challenges and future directions.
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Actes de Conférences |
Cao, S., Lequeux, M., Le Moal, E., Drezet, A., Huant, S., Dujardin, G., Boer-Duchemin, E. (2016). Using a plasmonic lens to control the emission of electrically excited light. In PROCEEDINGS OF SPIE (Vol. 9884, 98841Y).
Résumé: A local, low-energy, electrical method for the excitation of localized and propagating surface plasmon polaritons (SPPs) is attractive for both fundamental and applied research. In particular, such a method produces no excitation background light and may be integrated with nanoelectronics. Here we report on the electrical excitation of SPPs through the inelastic tunneling of low-energy electrons from the tip of a scanning tunneling microscope (STM) to the surface of a two-dimensional plasmonic lens. The plasmonic structure is a series of concentric circular slits etched in a thick gold film on a glass substrate. An out-going circular SPP wave is generated from the tip-sample junction and is scattered into light by the slits. We compare the resulting emission pattern to that observed when exciting SPPs on a thin, unstructured gold film. For optimized parameters, the light emitted from the plasmonic lens is radially polarized. We describe the effects of the slit period and number, and lens diameter on the emission pattern and we diskuss how the light beam of low divergence is formed.
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Chan, A., Clairand, M., Steenkeste, K., Eloy, M., Canette, A., Alousque, F., Ceccia, S., Gaboriaud, F., & Fontaine-Aupart, M. P. (2016). NR – Filler Interactions in aqueous condition by Multi-Modal Fluorescence and Electronic Microscopies. In Communications in Physics (Vol. ISSN 0868).
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Debiossac, M., & Roncin, P. (2016). Image processing for grazing incidence fast atom diffraction. In NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS (Vol. 382, 36).
Résumé: Grazing incidence fast atom diffraction (GIFAD, or FAD) has developed as a surface sensitive technique.
Compared with thermal energies helium diffraction (TEAS or HAS), GIFAD is less sensitive to thermal
decoherence but also more demanding in terms of surface coherence, the mean distance between defects.
Such high quality surfaces can be obtained from freshly cleaved crystals or in a molecular beam epitaxy
(MBE) chamber where a GIFAD setup has been installed allowing in situ operation. Based on recent pub-
lications by Atkinson et al. (2014) and Debiossac et al. (2014), the paper describes in detail the basic steps
needed to measure the relative intensities of the diffraction spots. Care is taken to outline the underlying
physical assumptions.
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Guilbaud, O., Kazamias, S., Cassou, K., Delmas, O., Demailly, J., Neveu, O., Ros, D., Baynard, E., Pittman, M., Shazad, M., Rossal, A., Tallents, G. J., Le Marec, A., Klisnick, A., Lu, L., Zeitoun, P., Cojocaru, G. V., Ungureanu, R. G., Banici, R. A., & Ursescu, D. (2016). Seeded Operation of a Ne-like Titanium Soft X-Ray Laser. In X-Ray Lasers 2014 (Vol. 169, pp. 61–67).
Résumé: Seeded operation of a Neon-like Titanium plasma-based soft x-ray laser is described. The plasma amplifier is pumped using a variation of the classical grazing incidence pumping technique, combining a long low energy pulse followed by a main short pulse. Because the preformed plasma is underionized, a part of the main short pulse energy is used to ionized it to the lasing stage. Consequences of this feature on seeded laser properties are discussed.
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Klisnick, A., Le Marec, A., Meng, L., Larroche, O., Guilbaud, O., Kozlova, M., Nejdl, J., & Calisti, A. (2016). Spectral Properties of Collisional Xuv Lasers for the Amplification of Femtosecond Pulses. In X-Ray Lasers 2014 (Vol. 169, pp. 45–52).
Résumé: We discuss the role of the spectral properties of XUV lasers in the amplification of femtosecond pulses in two different regimes. We present an overview of our recent spectral characterization of the four types of collisionally-pumped systems, also including other measurements from the literature. This is used to assess the potential of the different types of XUV lasers to amplify femtosecond pulses, either in the adiabatic or in the dynamic regime.
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Kozlova, M., Nejdl, J., Albrecht, M., Sebban, S., Gautier, J., Phuoc, K. T., Klisnick, A., Le Marec, A., & Tissandier, F. (2016). Overview of Development of Laser Driven Secondary Sources at PALS and ELI. In X-Ray Lasers 2014 (Vol. 169, pp. 35–43).
Résumé: In this paper we report on development of the secondary X-ray sources at the PALS Centre and discuss the plan for the ELI Beamlines project. The spatial and temporal coherence of the most energetic quasi-steady state Ne-like Zn X-ray laser, which is operated at PALS Centre as standard user beamline, was examined proving that amplification of coherent EUV pulses with duration below 1 ps will be possible. Meanwhile, the first transient lasing at PALS Center was achieved using 10 Hz Ti: Sapphire laser chain with peak power of 20 TW as a driver. Finally, we discuss the recent design of laser driven secondary sources generating short coherent or incoherent EUV/X-ray pulses within the ELI Beamlines project.
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Laversanne-Finot A., Ketterer A., Barros M. R., Walborn S. P., Coudreau T., Keller A., & Milman P. (2016). Contextually in a Peres-Mermin square using arbitrary operators. In Journal of Physics: Conference Series (Vol. 701, 012026).
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Le Marec, A., Kozlova, M., Nejdl, J., Meng, L., Tissandier, F., Guilbaud, O., Calisti, A., & Klisnick, A. (2016). Spectral and Coherence Properties of the Ne-like Zn X-Ray Laser at PALS. In X-Ray Lasers 2014 (Vol. 169, pp. 339–343).
Résumé: We present a refined measurement of the temporal coherence of the zinc X-ray laser generated at PALS, using a wavefront-division interferometer. The corresponding bandwidth of the lasing line is shown (i) to be broader than those of other types of X-ray lasers, previously characterized with the same instrument, and (ii) is compatible with the amplification of subpicosecond pulses. Similar measurements were also performed for shorter amplification lengths and the small-signal gain was carefully characterized.
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LeMarec, A., Larroche, O., Meng, L., & Klisnick, A. (2016). Temporal Response of Seeded XUV Lasers Under Different Amplification Regimes-Inversion Density Threshold. In X-Ray Lasers 2014 (Vol. 169, pp. 83–88).
Résumé: We present a simple model of amplification in XUV lasers which displays an inversion density threshold between a low-inversion, classical adiabatic regime and a high-inversion, dynamic regime involving Rabi oscillations. In the latter case, the small-signal gain is significantly smaller than the usually used adiabatic value, but the amplified pulse duration is no longer limited by the amplifier bandwidth. The dynamic regime can thus possibly lead to amplified femtosecond pulses.
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Marliere, C. (2016). A direct and at nanometer scale study of electrical charge distribution on membranes of alive cells. In Electro-Activity Of Biological Systems (Vol. 6).
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Sereno, M., Lupone, S., Debiossac, M., Kalashnyk, N., & Roncin, P. (2016). Active correction of the tilt angle of the surface plane with respect to the rotation axis during azimuthal scan. In NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS (Vol. 382, 123).
Résumé: A procedure to measure the residual tilt angle ττ between a flat surface and the azimuthal rotation axis of the sample holder is described. When the incidence angle θ and readout of the azimuthal angle ϕ are controlled by motors, an active compensation mechanism can be implemented to reduce the effect of the tilt angle during azimuthal motion. After this correction, the effective angle of incidence is kept fixed, and only a small residual oscillation of the scattering plane remains.
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Ursescu, D., Cojocaru, G., Ungureanu, R., Banici, R., Ionel, L., Simion, S., Dabu, R., Tummler, J., Jung, R., Stiel, H., Delmas, O., Pittman, M., Guilbaud, O., Kazamias, S., Cassou, K., Demailly, J., Neveu, O., Baynard, E., Ros, D., Le Marec, A., Daboussi, S., Lu, L., Klisnick, A., & Zeitoun, P. (2016). Transient Collisionally Excited X-ray Lasers Pumped with One Long and Two Short Pulses. In X-Ray Lasers 2014 (Vol. 169, pp. 53–59).
Résumé: X-ray laser simulations based on Ehybrid code have shown that enhanced plasma x-ray laser emission can be achieved mastering the ionization dynamics and plasma temperature using one long and two short pulses (Ursescu and Ionel, J Optoelectron Adv Mat 12: 48-51, 2010). In parallel, two simple methods to generate multiple short pulses for pumping x-ray lasers were reported in conjunction with x-ray laser developments. Five to ten fold enhancement in the emission of the silver x-ray laser was demonstrated using the newly developed pump methods, when compared with the traditional one, based on a long pulse followed by one short pump pulse. An overview of these recent experiments will be presented. The possible implementation of these novel x-ray laser pumping methods at Extreme Light Infrastructure-Nuclear Physics facility will be discussed.
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Monographies |
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Delaire, J., Piard, J., & Méallet-Renault, R. (2016). Photophysique et photochimie: Des fondements aux applications.
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Chapitres de Livres |
Kumar, N., Qui, P. X., Roopa, Leray, I., & Ha-Thi, M. - H. (2016). Calixarene-Based Fluorescent Molecular Sensors. In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier.
Résumé: In this present article, we present recent development of fluorescent molecular sensors based on calixarene for the detection of various species including cations, anions, and neutral molecules. The observed modulation of the fluorescence is because of perturbation of several photoinduced processes such as electron transfer, energy transfer, charge transfer, excimer formation and disappearance, chemodosimeter, and aggregation effect. The discussion clearly indicates the role of calixarene framework in developing selective and sensitive molecular sensor for a particular type of analyte.
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