Relaxation configurational entropy

We have seen that the cooperative region, which represents a nominal dynamical unit of liquid, is of rather modest size, resulting in observable fluctuation effects. Xia and Wolynes [45] computed the relaxation barrier distribution. The configurational entropy must fluctuate, with the variance given by the usual expression [77] 5Sc) ) = Cp barrier height for a particular region is directly related to the local density of states, and hence to... 

Here, tr is a dominant structural relaxation time of the liquid (e.g., viscosity p cx tr), T is temperature, Sc is the molar configurational entropy (defined... 

C. Adam-Gibbs Relation Between the Configurational Entropy Sc and Relaxation in Glass-Forming Liquids... 

Free Volume Versus Configurational Entropy Descriptions of Glass Formation Isothermal Compressibility, Specific Volume, Shear Modulus, and Jamming Influence of Side Group Size on Glass Formation Temperature Dependence of Structural Relaxation Times Influence of Pressure on Glass Formation... 

The thermodynamic functions of fc-mers adsorbed in a simple model of quasi-one-dimensional nanotubes s adsorption potential are exactly evaluated. The adsorption sites are assumed to lie in a regular one-dimensional space, and calculations are carried out in the lattice-gas approximation. The coverage and temperature dependance of the free energy, chemical potential and entropy are given. The collective relaxation of density fluctuations is addressed the dependence of chemical diffusion coefficient on coverage and adsorbate size is calculated rigorously and related to features of the configurational entropy. 

An independent assessment of the validity of the A G interpretation to the Cu+-induced relaxation (process B) was provided by direct estimation of the configurational entropy at the ferroelectric phase transition. The phase transition is dominated by a shift in the position of the Nb5+ ion in relation to the lattice. The coupling between the Cu+ ions and the Nb5+ polar clusters, evident in the paraelectric phase, will further contribute to the configuational entropy of the phase transition. 

The Kauzmann temperature plays an important role in the most widely applied phenomenological theories, namely the configurational entropy [100] and the free-volume theories [101,102]. In the entropy theory, the excess entropy ASex obtained from thermodynamic studies is related to the temperature dependence of the structural relaxation time xa. A similar relation is derived in the free-volume theory, connecting xa with the excess free volume AVex. In both cases, the excess quantity becomes zero at a distinguished temperature where, as a consequence, xa(T) diverges. Although consistent data analyses are sometimes possible, the predictive power of these phenomenological theories is limited. In particular, no predictions about the evolution of relaxation spectra are made. Essentially, they are theories for the temperature dependence of x.-jT) and r (T). 

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