Structural heterogeneities at the origin of acoustic and transport anomalies in glycerol glass-former

R Busselez and T Pezeril and VE Gusev, JOURNAL OF CHEMICAL PHYSICS, 140, 234505 (2014).

DOI: 10.1063/1.4883504

By means of large scale molecular dynamics simulations, we explore mesoscopic properties of prototypical glycerol glass-former above and below the glass transition. The model used, in excellent agreement with various experimental techniques, permits to carefully study the structure and the vibrational dynamics. We find that a medium range order is present in glycerol glass-former and arises from hydrogen bond network extension. The characteristic size of the structural heterogeneities is related to the anomalous properties of acoustic vibrations (Rayleigh scattering, "mode softening," and Boson Peak) in the glassy state. Finally the characteristic size of these heterogeneities, nearly constant in temperature, is also connected to the cross-over between structural relaxation and diffusion in liquid glycerol. (C) 2014 AIP Publishing LLC.

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