Section of Solid State Physics, Physics Department, University of Athens, Athens, Greece.
J Chem Phys. 2011 Dec 28;135(24):244508. doi: 10.1063/1.3666008.
Elastic models imply that the energy expended for a flow event in ultra-viscous matter coincides with the elastic work required for deforming and re-arranging the environment of the moving entity. This is quite promising for explaining the strong non-Arrhenius behavior of dynamic quantities of fragile super-cooled liquids. We argue that the activation volume obtained from dielectric relaxation and light-scattering experiments for super-cooled liquids should scale with the Gibbs free energy of activation, with a proportionality constant determined by the isothermal bulk modulus and its pressure derivative, as described by an earlier thermodynamic elastic model. For certain super-cooled liquids the bulk compression transpiring in the local environment, as governed by the isothermal bulk modulus, play a significant role in the reorientational dynamics, with far-field density fluctuations and volume changes avoided by shear deformation.
弹性模型表明，超粘性物质中流动事件所消耗的能量与变形和重新排列移动实体环境所需的弹性功相符。这对于解释脆性过冷液体的动态量的强非 Arrhenius 行为非常有希望。我们认为，从过冷液体的介电弛豫和光散射实验获得的激活体积应与激活吉布斯自由能成比例，比例常数由等温体弹性模量及其压力导数决定，如早期的热力学弹性模型所述。对于某些过冷液体，由等温体弹性模量控制的局部环境中的体压缩在重新取向动力学中起着重要作用，通过剪切变形避免了远场密度波动和体积变化。
