Thermodynamic anomalies in a lattice model of water

Abstract

We investigate a lattice-fluid model of water, defined on a three-dimensional body centered cubic lattice. Model molecules possess a tetrahedral symmetry, with four equivalent bonding arms, aiming to mimic the formation of hydrogen bonds. The model is similar to the one proposed by Roberts and Debenedetti [J. Chem. Phys. 105, 658 (1996)], simplified in that no distinction between bond "donors" and "acceptors" is imposed. Bond formation depends both on orientation and local density. In the ground state, we show that two different ordered (ice) phases are allowed. At finite temperature, we analyze homogeneous phases only, working out phase diagram, response functions, the temperature of maximum density locus, and the Kauzmann line. We make use of a generalized first-order approximation on a tetrahedral cluster. In the liquid phase, the model exhibits several anomalous properties observed in real water. In the low temperature region (supercooled liquid), there are evidences of a second critical point and, for some range of parameter values, this scenario is compatible with the existence of a reentrant spinodal.

Diffusion anomaly and dynamic transitions in the Bell–Lavis water model

“…In analogy to other two length scale interaction lattice models, [18][19][20][21] this model is expected to exhibit a region of density anomalies in its phase diagram. The phase diagram of this model was investigated for different values of the bonding strength, with different approaches: under a mean-field approach, 17,22,23 with renormalization group techniques 24,25 and very recently, through detailed numerical simulations.…”

Thermodynamic anomalies in a lattice model of water: Solvation properties

“…Nevertheless, the distinction between donors and acceptors is likely to be not so crucial to the physics of water. Therefore, in a previous paper 41 , we have investigated a simplified version of the model (without donor/acceptor distinction), showing that the same basic properties could be reproduced. Here we extend the simplified model to deal with aqueous solutions, working out solvation thermodynamics for an inert (apolar) solute.…”

“…This analysis might be interesting also in view of investigations on mixtures of water with more complex chemical species, such as polymers. We shall carry out the analysis by means of a generalized first-order approximation on a tetrahedral cluster, which has been verified to be quite accurate for the neat water model 41 .…”

Liquid polymorphism and density anomaly in a three-dimensional associating lattice gas

“…A number of lattice models in which the tetrahedral structure and the hydrogen bonds are present have been studied [44]- [48]. One of them, is the three-dimensional model proposed by Roberts and Debenedetti [46] and further studied by Pretti and Buzano [47] defined on the body centered cubic lattice. According to their approach, the energy between two bonded molecules rises when a third particle is introduced on A site neighbour to the bond.…”