The metastable T−P phase diagram and anomalous thermodynamic properties of supercooled water

Abstract

The metastable T−P phase diagram and the anomalies of the thermodynamic properties of supercooled water are calculated on the basis of a two-level thermodynamic model. Water is considered as a mixture of two components which differ in atomic configurations and correspond to low-density amorphous (lda) and high-density amorphous (hda) ice. The expression for the Gibbs potential of water is written in the form which is analogous to that of usual regular binary solutions. But this model considers the concentration, c, of the components, as a pressure and temperature-dependent internal parameter. There are only four constants in the expression for the Gibbs potential: the differences in the specific volumes, entropies, and energies of the two components and the mixing energy of the components whose values are ΔV0=−3.8 cm3/mol, ΔS0=4.225 J/mol, ΔE0=1037 J/mol, and U=3824 J/mol, respectively. The lda−hda phase equilibrium line terminates at the critical point, Tcr=230 K and Pcr=0.173 kbar, the second critical point in the phase diagram of water. The anomalous thermal dependence of the specific volume, the heat expansion coefficient, and the specific heat of water calculated for the atmospheric pressure is in a good quantitative agreement with the available experimental data. Thus anomalous properties of supercooled water are well explained by the occurrence of the second critical point close to the atmospheric pressure. The absolute value of parameter c is not crucial for the thermal behavior of properties, instead, the anomalies in water are due to the dependence on pressure and temperature. The parameter c behavior is analyzed in various pressure and temperature ranges around the second critical point. The thermal dependence of parameter c is very weak in the temperature range of 290–350 K at atmospheric pressure. As a consequence, the thermodynamic properties of water behave in this range like those of a normal liquid though water stays a mixture of two components, lda-like and hda-like, in an approximate proportion 2:3.

Multicritical phase diagrams of the ferromagnetic spin- Blume–Emery–Griffiths model with repulsive biquadratic coupling including metastable phases: The cluster variation method and the path probability method with the point distribution

“…Finally, it should be also mention that we have found that the metastable phase diagrams of the spin-3 2 Ising BEG model for K/Jp0, which has served as a paradigm for a large number of physically important phenomena, always exists at the low temperatures that are consistent with experimental and theoretical works on some alloys [39][40][41], semiconductors [42][43][44][45], polymers [46], water [47] and the ternary system [47]. Moreover, the spin-1 BEG model have been used to calculate the metastable phase diagrams of some real systems such as Cu-Al-Mn shape-memory alloys [41], semiconductor alloys [44,45] and the ternary system [48] and the unstable continuation of the second-order phase transition line in (A III B V ) 1Àx C IV 2 x -semiconductor alloys [45].…”

Multicritical phase diagrams of the Blume–Emery–Griffiths model with repulsive biquadratic coupling including metastable phases: the pair approximation and the path probability method with pair distribution

“…[5]. It should be also mention that we have found that the metastable phase diagrams of the BEG model for K=Jp0, which has served as a paradigm for a large number of physically important phenomena, always exists at the low temperatures that are consistent with experimental and theoretical works on some alloys [41][42][43], semiconductors [44,45] polymers [46], water [47] and the ternary system [48]. On the other hand, unstable phase transitions occur at low temperatures, which is also consistent with the work on ðA II B V Þ IÀX C IV 2X semiconductors alloys [49].…”

Multiple Amorphous–Amorphous Transitions

“…The hydrogen bond network in HDA is deformed strongly in a manner analogous to that found in water at high temperatures, whereas the pair correlation function of LDA is closer to that of supercooled water [183]. At ambient conditions, water was suggested to be a mixture of HDA-like and LDAlike states in an approximate proportion 2:3 [184][185][186].…”