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Digital.CSIC (158.952 recursos)

Repositorio institucional del Consejo Superior de Investigaciones Científicas. Digital.CSIC es un depósito de documentos digitales, cuyo objetivo es organizar, archivar, preservar y difundir en modo de acceso abierto la producción intelectual resultante de la actividad investigadora del CSIC.

(IEM) Artículos post-print

Mostrando recursos 1 - 20 de 42

  1. 6th Meeting of the Spanish Neutron Scattering Association (SETN2012): Preface

    Hernández-Velasco, Jorge; Cabrillo García, Carlos; Castellote, M.; Ruiz-Hervías, Jesús
    1 pag.; VI Reunión de la Sociedad Española de Técnicas Neutrónicas (SETN), Segovia, 24-27 de junio de 2012

  2. Poly(3-hexylthiophene) nanowires in porous alumina: Internal structure under confinement

    Martin, J.; Campoy Quiles, Mariano; Nogales, Aurora; Garriga, M.; Alonso, M. I.; Goñi, Alejandro R.; Martín-González, Marisol S.
    We study the structure of poly(3-hexylthiophene) (P3HT) subjected to nanoscale confinement in two dimensions (2D) as imposed by the rigid walls of nanopore anodic aluminum oxide (AAO) templates. P3HT nanowires with aspect ratios (length-to-diameter) above 1000 and diameters ranging between 15 nm and 350 nm are produced in the pores of the AAO templates via two processing routes. These are, namely, drying a solution or cooling from the melt. Our study focuses on the effects of nanoconfinement on the semicrystalline nature of the nanowires, the orientation of crystals, and the evolution of the structures that P3HT might develop under confinement,...

  3. Physicochemical modifications accompanying UV laser induced surface structures on poly(ethylene terephthalate) and their effect on adhesion of mesenchymal cells

    Rebollar, Esther; Pérez, Susana; Hernández, Margarita; Domingo, Concepción; Martín, Margarita; Ezquerra, Tiberio A.; García-Ruiz, Josefa P.; Castillejo, Marta
    This work reports on the formation of different types of structures on the surface of polymer films upon UV laser irradiation. Poly(ethylene terephthalate) was irradiated with nanosecond UV pulses at 193 and 266 nm. The polarization of the laser beam and the irradiation angle of incidence were varied, giving rise to laser induced surface structures with different shapes and periodicities. The irradiated surfaces were topographically characterized by atomic force microscopy and the chemical modifications induced by laser irradiation were inspected via micro-Raman and fluorescence spectroscopies. Contact angle measurements were performed with different liquids, and the results evaluated in terms of...

  4. Ethane internal rotation-Vibrational Hamiltonian

    Hidalgo-Olguín, D.R.; Villa, M.; Senent, María Luisa; Mora-Delgado, M.A.
    One of the main purposes of a theoretical spectroscopist is to propose a model to reproduce the xperimental spectra available in the literature as accurate and with as much physical information as possible. In this case it has been studied the Far infrared an Infrared spectra of non-rigid molecules, introducing in the Vibrational Potential their dependence on the large amplitude variables. The molecule that has been selected to test our proposed Hamiltonian is ethane which is a very well studied molecule. The molecule is a non-rigid molecule and their experimental spectra have been reported in the literature. © 2008, Sociedad...

  5. Argon induced bottleneck in the IR multiphoton dissociation of C 3F6

    Rubio, L; Santos, M.; Torresano, J.A.
    In this work, the effect of added argon (0 to 7.5 hPa) on the collisional mechanisms involved in the infrared multiphoton dissociation of hexafluoropropene (0.1 to 0.8 hPa) at a constant irradiation fluence is studied. The study has been carried out in a quantitative way by applying the extended McRae et al., model. The variation of the different model parameters as a function of argon pressure has been obtained. The results confirm the role played by argon in the occurrence of a significant bottleneck effect in C 3F6. leading to a switch in the behaviour of this molecule in relation...

  6. Nuclear structure aspects of atomic parity violation in Barium

    Moreno, O.; Navarro de Martino, E.; Moya de Guerra, Elvira; Sarriguren, Pedro
    The weak interaction between an atomic nucleus and the orbiting electrons is responsible for small parity mixings in the electron wave functions that give rise to atomic transitions forbidden between pure-parity states. The degree of the parity mixing, and thus the strength of the nominally forbidden atomic transitions, depends on the weak charge of the nucleus, driven mainly by the neutron distribution. We focus in this work on polarized electron elastic scattering by nuclei as a tool to extract information on the nuclear weak charge and radius needed to analyze atomic parity violation measurements. A set of Barium isotopes of...

  7. Platinum Nanoparticles as Photoactive Substrates for Mass Spectrometry and Spectroscopy Sensors

    Cueto, Maite; Piedrahita, Mauricio; Caro Salazar, Carlos Alberto; Martínez-Haya, Bruno; Sanz, Mikel; Oujja, Mohamed; Castillejo, Marta
    8 pags. ; 6 figs.

  8. Elastic scattering of 8He + 208Pb at 22 MeV

    Sánchez-Benítez, A. M.; Martel, Ismael; Acosta, Luis; Álvarez, M. A. G.; García Borge, María José; Cruz, C.; Cubero, M.; Fernández García, J. P.; Fernández-Martínez, B.; Gómez-Camacho, Joaquín; Labrador, J. A.; Moro, A. M.; Pesudo, V.; Tengblad, Olof; Abou-Haidar, Ziad
    Presented at the Zakopane Conference on Nuclear Physics “Extremes of the Nuclear Landscape”, Zakopane, Poland, August 27–September 2, 2012.-- et al.

  9. Exact study of the effect of level statistics in ultrasmall superconducting grains

    Sierra, Germán; Dukelsky, Jorge; Dussel, G. G.; Von Delft, J.; Braun, Fabian
    The reduced BCS model that is commonly used for ultrasmall superconducting grains has an exact solution worked out long ago by Richardson in the context of nuclear physics. We use it to check the quality of previous treatments of this model, and to investigate the effect of level statistics on pairing correlations. We find that the ground-state energies are on average somewhat lower for systems with nonuniform than uniform level spacings, but both have an equally smooth crossover from the bulk to the few-electron regime. In the latter, statistical fluctuations in ground-state energies strongly depend on the grain's electron number...

  10. Assessment of femtosecond laser induced periodic surface structures on polymer films

    Rebollar, Esther; Vázquez de Aldana, Javier R.; Martín-Fabiani, Ignacio; Hernández, Margarita; Rueda, Daniel R.; Ezquerra, Tiberio A.; Domingo, Concepción; Moreno, Pablo; Castillejo, Marta
    In this work we present the formation of laser induced periodic surface structures (LIPSS) on spin-coated thin films of several model aromatic polymers including poly(ethylene terephthalate), poly(trimethylene terephthalate) and poly carbonate bis-phenol A upon irradiation with femtosecond pulses of 795 and 265 nm at fluences well below the ablation threshold. LIPSS are formed with period lengths similar to the laser wavelength and parallel to the direction of the laser polarization vector. Formation of LIPSS upon IR irradiation at 795 nm, a wavelength at which the polymers absorb weakly, contrasts with the absence of LIPSS in this spectral range upon irradiation...

  11. Temporal evolution study of the plasma induced by CO2 pulsed laser on targets of titanium oxides

    Díaz Sol, Luis; Camacho, J. J.; Sanz, M.; Hernández, M.; Jandova, V.; Castillejo, Marta
    This paper reports studies on time-resolved laser induced breakdown spectroscopy (LIBS) of plasmas induced by IR nanosecond laser pulses on the titanium oxides TiO and TiO2 (anatase). LIBS excitation was performed using a CO2 laser. The laser-induced plasma was found strongly ionized yielding Ti+, O+, Ti2 +, O 2 +, Ti3 +, and Ti4 + species and rich in neutral titanium and oxygen atoms. The temporal behavior of specific emission lines of Ti, Ti+, Ti2 + and Ti3 + was characterized. The results show a faster decay of Ti3 + and Ti 2 + ionic species than that of Ti+...

  12. Infrared and Raman spectra and normal coordinate analysis of disilylchloride

    Ben Altabef, Aída; Escribano, Óscar
    Disilylchloride has been synthesized by chlorination of disilane with boron trichloride. FTIR spectra have been obtained of the vapour phase and Raman spectra of the liquid phase of this molecule. The spectra are fully assigned for the first time. A normal coordinate analysis is carried out and the refined force constants are compared to previous works on disilane, disilyliodide and silylchloride. The height of the potential energy barrier to internal rotation in disilylchloride is also evaluated. © 1991.

  13. High-resolution infrared spectrum of the ν1 band of OClO

    Ortigoso, Juan; Escribano, Rafael; Burkholder, James B.; Howard, Carleton J.; Lafferty, Walter J.
    The infrared absorption spectrum of the ν1 band of OClO (care must be taken to distinguish it from ClOO, which also exists) has been recorded in the 950 cm-1 region, with a Fourier transform infrared spectrometer with an instrumental resolution of ∼0.004 cm-1. Most lines appear as doublets owing to the spin-rotation interaction present in this molecule. Around 2800 lines have been assigned for the 35ClO2 species and ∼800 for the 37ClO2 species. In addition, a number of lines of the >hot band>, ν1 + ν2 - ν2, have been assigned for the 35ClO2 species. Effective rotational and spin-rotational spectroscopic...

  14. Empirical anharmonic force field and equilibrium structure of hypochlorous acid, HOCl

    Escribano, Rafael; Di Lonardo, G.; Fusina, L.
    The cubic and quartic force fields of HOCl are investigated on the basis of the most recent experimental data on vibration-rotation interaction constants and anharmonicity constants. Some discrepancies with respect to previously reported ab initio results are found and discussed. The geometrical parameters of this molecule are also evaluated from recent data on the equilibrium values of the moments of inertia.© 1996 Published by Elsevier B.V.

  15. Absolute Raman intensities of CH4, CH3D, CH2D2, CHD3, and CD4

    Bermejo, Dionisio; Escribano, Rafael; Orza, J. M.
    Measurements of the absolute vibrational Raman intensities and depolarization ratios for the fundamental and some overtone and combination bands of CH4, CH3D, CH2D2, CHD3, and CD4 are reported. Experimental aspects of these measurements are discussed. The experimental data conform satisfactorily to all isotope intensity sum rules. The measured intensities and depolarization ratios, together with the vibrational potential function for CH4, make possible the calculation of the four independent parameters of the isotopic invariant quantities αS = | ∂α ∂S|. The results deduced from these agree with all 36 experimentally observed values. Values of electro-optical parameters for the CH bond are...

  16. Experimental and theoretical study of line mixing in methane spectra. II. Influence of the collision partner (He and Ar) in the v3 IR band

    Pieroni, D.; Nguyen-Van-Thanh, C.; Brodbeck, C.; Hartmann, Jean-Michel; Gabard, T.; Champion, J.-P.; Bermejo, Dionisio; Doménech, José Luis; Claveau, C.; Valentin, A.; Tonkov, M.V.; Grigoriev, I.M.; Le Doucen, R.
    Line mixing effects are studied in the v3 band of CH4 perturbed by Ar and He at room temperature. Experiments have been made in the 2800-3200 cm-1 spectral region using four different setups. They cover a wide range of total densities, including low (0.25-2 atm), medium (25-100 atm), and high (200-1000 atm) pressure conditions. Analysis of the spectra demonstrates that the spectral shapes (of the band, the Q branch, the P and R manifolds,...) are significantly influenced by line mixing. The theoretical approach proposed in the preceding paper is used in order to model and analyze these effects. As done...

  17. A partially correlated strong collision model for velocity-and state-changing collisions application to Ar-broadened HF rovibrational line shape

    Joubert, P.; Bonamy, J.; Robert, D.; Doménech, José Luis; Bermejo, Dionisio
    High-resolution tunable laser measurements of rovibrational line shapes in Arbroadened HF [A.S. Pine, J. Chem. Phys., 1994, 101, 3444] have shown the need of partially correlated Dicke narrowing models to accurately describe the observed asymmetries. A strong collision model accounting for both velocity-and state-changing mechanisms (VCD) and phase-changing ones (D), is presented. The resulting line shape justifies, on a physical basis, the empirical model previously used to interpret the observed features. The present partially correlated strong collisional model leads to a clearer interpretation of the characteristic parameters determined from the experiment for HF-Ar. Further theoretical calculations and experiments show that...

  18. Absolute Line Intensities in the 2v3 Band of 16O12C32S

    Bermejo, Dionisio; Doménech, José Luis; Santos, Julio; Bouanich, Jean-Pierre; Blanquet, Ghislain
    The strengths of 100 lines in the 2v3 band of 16O12C32S have been measured at high resolution in the spectral range 4069-4118 cm-1, using a tunable difference-frequency laser spectrometer. These intensities were obtained by fitting Voigt profiles to the measured shapes of the lines. The vibrational transition moment [(2.141 ± 0.020) × 10-2 D] and the absolute intensity (16.19 ± 0.24 cm-2 atm-1 at 296 K) of the 2v3 band of 16O12C32S are determined from these linestrength measurements. © 1997 Academic Press.

  19. Cold crystallization studies on PET/PEN blends as revealed by microhardness

    Connor, Marco T.; García-Gutiérrez, Mari Cruz; Rueda, Daniel R.; Baltá Calleja, Francisco José
    The cold crystallization of amorphous films of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) blends, with different composition, prepared by co-precipitation from solution followed by melt-pressing for 2 min at 280°C and quenching in ice water, was followed by measuring the microhardness, H, in real time as a function of crystallization temperature and time. An analytical model was derived, relating properties of the individual components to the blend microhardness based on an Avrami-type equation to account for the crystallization of the components upon heating. Fitting of the model to the experimental results revealed a two-step hardening process of the blends....

  20. Influence of water on the dielectric behaviour of chitosan films

    Nogales, Aurora; Ezquerra, Tiberio A.; Rueda, Daniel R.; Martínez, Francisco; Retuert, Jaime
    The dielectric properties of chitosan films with a degree of deacetylation of 86% have been investigated in the frequency range of 103-106 Hz covering a broad range of temperatures from -150 to 150 °C. The variation of the dielectric properties with temperature has been associated with two dielectric processes: (a) a local relaxation attributed to the presence of hydrogen-bonded water appearing at low temperatures (b) a conduction process related to water molecules which becomes desorbed upon heating at T > 80 °C. Isothermal dielectric experiments have been performed in order to follow, in real time, the occurrence of both, the...

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