M. D. Ruiz-Martín

Publications (5)3.33 Total impact

• Source

  Available from: Gabriel J Cuello

  Article: Microscopic structure and dynamics of high and low density trans-1,2-dichloroethylene liquids

  M. Rovira-Esteva, A. Murugan, L C Pardo, S. Busch, M. D. Ruiz-Martín, M. -S. Appavou, J Ll Tamarit, C. Smuda, T. Unruh, F J Bermejo, G J Cuello, S J Rzoska
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  ABSTRACT: We present a study of the dynamics and structural changes for trans-1,2-dichloroethylene between high and low density liquids using neutron scattering techniques (diffraction, small angle neutron scattering and time of flight spectroscopy) and molecular dynamics simulations. We show that changes in the short range ordering of molecules goes along with a change of the molecular dynamics: both structure and dynamics of the high density liquid are more cooperative than those of the low density liquid. The microscopic mechanism underlying the cooperative motions in the high density liquid has been found to be related to the backscattering of molecules due to a strong correlation of molecular ordering. Comment: 5 pages and 3 figures. To be published in Physical Review B
  02/2010;
• Article: Correlated atomic motions in liquid deuterium fluoride studied by coherent quasielastic neutron scattering.

  F Fernandez-Alonso, S E McLain, J W Taylor, F J Bermejo, I Bustinduy, M D Ruiz-Martín, J F C Turner
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  ABSTRACT: The collective dynamics of liquid deuterium fluoride are studied by means of high-resolution quasielastic and inelastic neutron scattering over a range of four decades in energy transfer. The spectra show a low-energy coherent quasielastic component which arises from correlated stochastic motions as well as a broad inelastic feature originating from overdamped density oscillations. While these results are at variance with previous works which report on the presence of propagating collective modes, they are fully consistent with neutron diffraction, nuclear magnetic resonance, and infrared/Raman experiments on this prototypical hydrogen-bonded fluid.
  The Journal of Chemical Physics 07/2007; 126(23):234509. · 3.33 Impact Factor
• Article: High frequency collective excitations in molten Fe/Ni alloys studied by inelastic neutron scattering

  M. Jiménez-Ruiz, M. D. Ruiz-Martín, G J Cuello, Ricardo Fernández-Perea, Francisco Javier Bermejo
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  ABSTRACT: 3 pages, 2 figures.-- Available online on Jan 20, 2007.-- Issue title: Proceedings of the 12th International IUPAC Conference on High Temperature Materials Chemistry-HTMC XII (Vienna, Austria, Sep 17-22, 2006). The spectra of liquid 85%Fe5%Ni10%S (Tm = 1650 K) and liquid 85%Fe15%Ni have been studied by means of inelastic neutron scattering. Our aim was to explore at high frequencies some observed anomalies as reported from ultrasound studies. Contrary to the behavior of the pure liquid-metals, the phase velocity of the observed excitation for the sulfur-containing sample increases with temperature while their damping decreases. On the other hand, data of the binary Fe/Ni alloy do not show such an anomalous behavior. Peer reviewed
• Article: Microscopic structures and dynamics of high-and low-density liquid trans-1, 2-dichloroethylene

  M. Rovira-Esteva, A. Murugan, L. C. Pardo, S. Busch, M. D. Ruiz-Martín, M.-S. Appavou, J. Ll. Tamarit, C. Smuda, T. Unruh, F. J. Bermejo, G. J. Cuello, S. J. Rzoska
  [show abstract] [hide abstract]
  ABSTRACT: We present a study of the dynamics and structural changes for trans-1,2-dichloroethylene between high- and low-density liquids using neutron-scattering techniques (diffraction, small-angle neutron scattering, and time of flight spectroscopy) and molecular-dynamics simulations. We show that changes in the short-range ordering of molecules goes along with a change in the molecular dynamics: both structure and dynamics of the high-density liquid are more cooperative than those of the low-density liquid. The microscopic mechanism underlying the cooperative motions in the high-density liquid has been found to be related to the backscattering of molecules due to a strong correlation of molecular ordering.
  Phys. Rev. B. 81(9).
• Article: High-frequency collective excitations in molten and glassy Te studied by inelastic neutron scattering

  M. D. Ruiz-Martín, M. Jiménez-Ruiz, F. J. Bermejo, R. Fernández-Perea
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  ABSTRACT: The spectra of collective excitations of liquid and glassy tellurium have been studied by means of inelastic neutron scattering. Here we report on the dynamics of liquid Te as measured at two different temperatures, just above melting (Tm=723 K) and at ∼1000 K as well as the glass that is studied at room temperature. Estimates for the velocity of propagating excitations for both temperatures have been obtained from the experimental data, and a contrasting behavior is found with respect to anomalies shown by the adiabatic sound velocity measured by ultrasound methods. The origin of such differences is finally discussed.
  Phys. Rev. B. 73(9).