Publications

Showing 198 results for Author: Alexei P. Sokolov

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  • Apr, 2011

    Journal

    Is There a Connection Between Fragility of Glass Gorming Systems and Dynamic Heterogeneity/Cooperativity?

    Although fragility of glass forming liquids is traditionally related to cooperativity in molecular motion, the connection between those parameters remains unclear. In this paper we present the estimates of cooperativity (heterogeneity) length scale ξ obtained from the boson peak spectra. We demonstrate that ξ agrees well with the dynamic heterogeneity length scale for the…

  • Apr, 2011

    Journal

    Appearance of a Debye process at the Conductivity Relaxation Frequency of a Viscous Liquid

    The existence of a Debye-type ultraslow process in dielectric spectra of bulk polyalcohols and similar materials has been reported repeatedly in the recent literature. Its loss peak is observed at frequencies that are decades below those of the primary structural relaxation, in a range where the loss signal is usually dominated by dc-conductivity or even electrode polariza…

  • Apr, 2011

    Journal

    Dynamics of Biological Macromolecules: Not a Simple Slaving by Hydration Water

    We studied the dynamics of hydrated tRNA using neutron and dielectric spectroscopy techniques. A comparison of our results with earlier data reveals that the dynamics of hydrated tRNA is slower and varies more strongly with temperature than the dynamics of hydrated proteins. At the same time, tRNA appears to have faster dynamics than DNA. We demonstrate that a similar diff…

  • Mar, 2011

    Journal

    Influence of Pressure on Fast Picosecond Relaxation in Glass-Forming Materials

    Understanding the microscopic mechanism of the fast dynamics (gigahertz-terahertz frequency range) in amorphous materials remains a challenge. Disordered systems usually exhibit two additional contributions in this frequency range in comparison to their crystalline counterparts: a low-frequency excess vibrations, the so-called boson peak, and the fast picosecond relaxation…

  • Mar, 2011

    Journal

    Size of the Dynamic Bead in Polymers

    Presented analysis of neutron, mechanical, and MD simulation data available in the literature demonstrates that the dynamic bead size (the smallest subchain that still exhibits the Rouse-like dynamics) in most of the polymers is significantly larger than the traditionally defined Kuhn segment. Moreover, our analysis emphasizes that even the static bead size (e.g., chain st…

  • Apr, 2010

    Journal

    Molecular cooperativity in the dynamics of glass-forming systems: A new insight

    The mechanism behind the steep slowing down of molecular motions upon approaching the glass transition remains a great puzzle. Most of the theories relate this mechanism to the cooperativity in molecular motion. In this work, we estimate the length scale of molecular cooperativity for many glass-forming systems from the collective vibrations the so-called boson peak. T…

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