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

Abstract

We investigate the phase diagram of a three-dimensional associating gas (ALG) model. This model combines orientational ice-like interactions and "van der Waals" that might be repulsive, representing, in this case, a penalty for distortion of hydrogen bonds. These interactions can be interpreted as two competing distances making the connection between this model and continuous isotropic soft-core potentials. We present Monte Carlo studies of the ALG model showing the presence of two liquid phase, two critical points and A density anomaly.

Structure and anomalous solubility for hard spheres in an associating lattice gas model

“…[7][8][9] Even though there are a number of two and three dimensional lattice models that would in principle exhibit the anomalies present in water, 6,16,[19][20][21] here water is represented by the associating lattice gas (ALG) (Refs. [22][23][24][25][26][27][28]) that has already shown the density and diffusion anomalies described above. The ALG does not have the full complexity of the molecular liquid, however it leads to a network-forming fluid in which directionality plays an important role.…”

“…26 Dynamic and thermodynamic properties of the system were previously obtained by Monte Carlo simulations 26,28,29 and analytical methods. 30 The model consists of a body centered cubic lattice where sites can be either occupied (σ i = 1) by a water molecule or empty (σ i = 0).…”

Dynamic transitions in a three dimensional associating lattice gas model

“…13 Here we address these questions by studying the associating lattice gas model that exhibits two liquid phases and different ordered phases. This waterlike model has density and diffusion anomalies 14,15 and its phase diagram has been investigated previously through Monte Carlo simulations 14 and cluster expansions. 16 In the numerical study of the model by Girardi et al 14,15 two coexisting liquid phases, as well as density and diffusion anomalies were found.…”

Molecular mean field theory for liquid water

“…A significant equilibriation time is allowed before the production run begins. In In order to obtain equation of state using MC we employed fixed temperature simulations, followed by application of Gibbs-Duhem procedure to obtain pressure versus density curves [11,28,29]. In theμV T ensemble temperature is fixed and a range of chemical potentials are explored starting from zero density where pressure can be normalized to the value zero.…”