Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior

Details Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior

2008-06-05

arxiv.org/abs/0806.0958v3

Physics

Condensed Matter

Statistical Mechanics

12 pages, 7 figures

Scientific paper

10.1103/PhysRevE.78.051115

In a preceding paper, Mukhopadhyay and I studied the diffusive motion of a tagged molecule in a heterogeneous glass-forming liquid at temperatures just above a glass transition. Among other features of this system, we postulated a relation between heterogeneity and stretched-exponential decay of correlations, and we also confirmed that systems of this kind generally exhibit non-Gaussian diffusion on intermediate length and time scales. Here I extend this analysis to higher temperatures approaching the point where the heterogeneities disappear and thermal activation barriers become small. I start by modifying the continuous-time random-walk theory proposed earlier, and supplement this analysis with an extension of the excitation-chain theory of glass dynamics. I also use a key result from the shear-transformation-zone theory of viscous deformation of amorphous materials. Elements of each of these theories are then used to interpret experimental data for ortho-terphenyl, specifially, the diffusion and viscosity coefficients and neutron scattering measurements of the self intermediate scattering function. Reconciling the theory with these data sets provides insights about the crossover between super-Arrhenius and Arrhenius dynamics, length scales of spatial heterogeneities, violation of the Stokes-Einstein relation in glass-forming liquids, and the origin of stretched exponential decay of correlations.

Affiliated with

Also associated with

No associations

Rating

Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Anomalous diffusion in heterogeneous glass-forming liquids: Temperature-dependent behavior will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-128037