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

TL;DR

This study explores a 3D associating lattice gas model revealing liquid polymorphism, density anomalies, and critical points, linking orientational interactions with soft-core potential behaviors.

Contribution

It introduces a novel 3D associating lattice gas model combining orientational and repulsive interactions, demonstrating complex phase behavior including multiple liquid phases and anomalies.

Findings

Presence of two liquid phases

Identification of two critical points

Observation of density anomaly

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.