Two-order-parameter model of liquid: Water-like thermodynamic anomaly, liquid-liquid transition, and liquid-glass transition

2004 ◽  
Author(s):  
Hajime Tanaka
Keyword(s):  
Glass Transition ◽  
Liquid Water ◽  
Liquid Glass ◽  
Order Parameter ◽  
Liquid Transition

Description of the Glass Transition by a Percolation Blocking of Local Chemical Order

1996 ◽  
Vol 51 (1-2) ◽  
pp. 87-94 ◽  
Author(s):  
J. Blétry
Keyword(s):  
Glass Transition ◽  
Cooling Rate ◽  
Liquid Glass ◽  
Order Parameter ◽  
Irreversible Thermodynamics ◽  
General Description ◽  
Thermodynamical Equilibrium ◽  
Chemical Order ◽  
Metallic Liquids ◽  
Silicon And Germanium

Abstract A model for the liquid-glass transition, based on a percolation blocking of local chemical order, is proposed. The case of metallic liquids and glasses, whose structure is dominated by first neighbour chemical arrangement, is first treated. The chemical ordering "reaction" of the liquid phase is studied at thermodynamical equilibrium and the increase of the chemical order parameter with decreasing temperature is calculated. Within a given composition interval, however, a geometrical percolation process is shown to block this reaction below a "percolation temperature" (corresponding to null cooling rate) where the liquid is irreversibly frozen into a glass. The liquid-glass "phase diagram" is established and kinetic arguments, involving "frustrated" finite clusters which are formed close to the percolation threshold, provide an evaluation of the experimentally measured "glass transition temperature" as a function of cooling rate. The validity of this one order parameter model is then discussed with the help of the irreversible thermodynamics theory of Prigogine.The formation of tetracoordinated glasses is explained by the formation of tetrahedral bonds, when the liquid temperature decreases, and represented by a "hole ordering" reaction. A general description of the structure of tetracoordinated glasses is thus achieved, which applies to amorphous silicon and germanium, 111 -V compounds, silica, amorphous water etc. Furthermore, an estimation of the temperature interval for the glass transformation of silica is obtained, which agrees well with experiment.The existence of frustrated clusters gives to glasses a composite structure in the "medium distance order", which could explain the "fractal nature" of glass fracture surfaces down to the nanometer scale.

Slow Dynamics Due to the Metal-Nonmetal Transition in Liquids

2003 ◽  
Vol 217 (7) ◽  
pp. 803-816 ◽  
Author(s):  
Makoto Yao ◽  
Hirotaka Kohno ◽  
Hiroaki Kajikawa
Keyword(s):  
Relaxation Time ◽  
Glass Transition ◽  
Liquid Glass ◽  
Sound Attenuation ◽  
Slow Dynamics ◽  
Anomalous Increase ◽  
Relaxation Strength ◽  
Transition Range ◽  
Liquid Dynamics ◽  
Nonmetal Transition

AbstractIt is well known that the liquid dynamics slows down on approaching the liquid-gas critical point or the liquid-glass transition. Recently we have found by the sound attenuation measurements that the metal-nonmetal (M-NM) transition also induces slow dynamics. In the M-NM transition range of expanded liquid Hg, we have observed anomalous increase in the sound attenuation due to the structural relaxation process. Assuming a simple Debye-type relaxation, we have estimated that the relaxation time should be of the order of nanoseconds and revealed that the relaxation strength has a broad maximum in the M-NM transition range. Moreover, two types of anomalies have been observed also in the semiconductor-metal (S-M) transition range of liquid Te-Se mixtures. We present the recent experimental results of the sound attenuation measurements and discuss briefly the mechanisms of the slow dynamics in the metal-nonmetal transition range of liquids.

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