Fast dynamics perspective on the breakdown of the Stokes-Einstein law in fragile glassformers

Abstract

The breakdown of the Stokes-Einstein (SE) law in fragile glassformers is examined by Molecular-Dynamics simulations of atomic liquids and polymers and consideration of the experimental data concerning the archetypical OTP glassformer. All the four systems comply with the universal scaling between the viscosity (or the structural relaxation) and the Debye-Waller factor $⟨u^2⟩$, the mean square amplitude of the particle rattling in the cage formed by the surrounding neighbors. It is found that the SE breakdown is scaled in a master curve by a reduced $⟨u^2⟩$. Two approximated expressions of the latter, with no and one adjustable parameters respectively, are derived.

arXiv commentaccepted for publication in J Chem Phys

References in corpus (10)

• Theoretical perspective on the glass transition and amorphous materials
• Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture I: The van Hove Correlation Function
• Predicting the long time dynamic heterogeneity in a supercooled liquid on the basis of short time heterogeneities
• Neutron Scattering Studies of the Model Glass Former Ortho-terphenyl
• Universal divergenceless scaling between structural relaxation and caged dynamics in glass-forming systems
• Thermodynamic scaling of vibrational dynamics and relaxation
• The kinetic fragility of liquids as manifestation of the elastic softening
• Scaling between structural relaxation and caged dynamics in Ca_{0.4}K_0.6(NO_{3})_{1.4} and glycerol: free volume, time scales and implications for the pressure-energy correlations
• Dynamical, structural and chemical heterogeneities in a binary metallic glass-forming liquid
• Assessment of elastic models in supercooled water: A molecular dynamics study with the TIP4P/2005f force field

Cited by in corpus (6)

• Excess entropy determines the applicability of Stokes-Einstein relation in simple fluids
• Elementary vibrational model for transport properties of dense fluids
• Molecular layers in thin supported films exhibit the same scaling as the bulk between slow relaxation and vibrational dynamics
• Classification of mobile- and immobile-molecule timescales for the Stokes-Einstein and Stokes-Einstein-Debye relations in supercooled water
• Fast Vibrational Modes and Slow Heterogeneous Dynamics in Polymers and Viscous Liquids
• Violation of Stokes-Einstein and Stokes-Einstein-Debye relations in polymers at the gas-supercooled liquid coexistence