Lattice model of a polar liquid

The molecular model of a polar liquid based on the lattice gas theory was used to study the liquid—gas phase equilibrium. In this theory, the key unknown variables are the probabilities of various mutual pair positions of the molecules. The molecules are considered as non-polarizable point dipoles. The intermolecular interaction potential includes a dipole—dipole component depending on the molecular orientation and the Lennard-Jones contribution stabilizing the system with dipole interactions. The theory provides qualitative agreement with experimental data on the water—vapor equilibrium.