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Ulf R. Pedersen

Publications and source records attributed to Ulf R. Pedersen.

38 records · Page 3Linked to original sources

An energy landscape model for glass forming liquids in three dimensions

We present a three-dimensional lattice-gas model with trivial thermodynamics, but nontrivial dynamics. The model is characterized by each particle having its own random energy landscape. The equilibrium dynamics of the model were investigated by continuous time Monte Carlo simulations at two different densities at several temperatures. At high densities and low temperatures the model captures the important characteristics of viscous liquid dynamics. We thus observe non-exponential relaxation in the self part of the density auto-correlation function, and fragility plots of the self-diffusion constant and relaxation times show non-Arrhenius behavior.

cond-mat.soft↗

A single-frequency test for one-parameter models of the linear thermo-visco-elastic response of glass-forming liquids

A master equation description of the inherent dynamics is used to calculate the frequency-dependent linear thermo-visco-elastic response functions of a glass-forming liquid. From the imaginary parts of the isobaric specific heat, isothermal bulk modulus, and isobaric thermal expansion coefficient, we define a quantity $Λ_{Tp}(ω)$ with the property that $Λ_{Tp}(ω)=1$ is equivalent to having a one-parameter description of the linear thermo-visco-elastic response. This provides an alternative to the well-known criterion based on the Prigogine-Defay ratio.

cond-mat.stat-mech↗