Towards the Development of a Universal Expression for the Configurational Entropy of Mixing

Entropy

Jorge Garcés¹ 

[1]Nuclear Material Department, GIA, GAATN, Bariloche Atomic Center, 8400 Bariloche, Río Negro, Argentina

关键词: configurational entropy;    analytical expressions;    interstitial solid solutions;    non-crystalline state of matter;    equation of state;    hard sphere system;    percolation thresholds;   

DOI  :  10.3390/e18010005

来源: mdpi

【 摘 要 】

This work discusses the development of analytical expressions for the configurational entropy of different states of matter using a method based on the identification of the energy-independent complexes (clustering of atoms) in the system and the calculation of their corresponding probabilities. The example of short-range order (SRO) in Nb-H interstitial solid solution is used to illustrate the choice of the atomic complexes and their structural changes with H concentration, providing an alternative methodology to describe critical properties. The calculated critical composition of the miscibility gap is x_c = 0.307,in remarkable agreement with the experimental value of x_c ~ 0.31. The same methodology is applied to deduce the equation of state (EOS) of a hard sphere system. The EOS is suitable to describe the percolation thresholds and fulfills both the low and random close packing limits. The model, based on the partition of the space into Voronoi cells, can be applied to any off-lattice system, thus introducing the possibility of computing the configurational entropy of gases, liquids and glasses with the same level of accuracy.

【 授权许可】

CC BY   
© 2015 by the author; licensee MDPI, Basel, Switzerland.