Modified molecular model for the description of condensed phases of heavy water

Using the lattice dynamics method, a simple three-point model of heavy water has been proposed by optimizing thermal expansion and the melting temperature of deuterated hexagonal ice Ih to the experimental values through the parameters of the Lennard-Jones and Coulomb potentials between sites with fixed charges, which describe the interactions between water molecules. The lattice dynamics method includes the energy of zero-point vibrations, which allows more accurate construction of thermodynamic functions. The density of vibrational states, temperature dependence of the linear sizes of the unit cell, and the melting temperature of ice Ih at various concentrations of the D$_2$O molecules have been calculated.