An interionic force law for HgCl2 from first-principles molecular calculations

Mercury dichloride is an ionic compound solidifying into a unique layer structure of rod-like monomers, so that unusual structural and physical properties can be expected for its liquid state. We propose a set of pseudoclassical interionic potentials, including three-body forces and electronic-polarization terms, patterned on the results of relativistic first-principles calculations on the molecular monomer, dimer and trimer. The proposed force law will allow structural studies of the condensed phases by molecular-dynamics simulations, with the main aims of exploring the nature of the short-range and intermediate-range order in the melt and the process of ionization at high pressure and temperature.