Pair Potentials from ab initio Calculations for use in MD Simulations of Molten Alkali Carbonates

Abstract

Abstract Ab initio calculations at the Hartree-Fock SCF level have been carried out to determine the pair interaction between the alkali ions and the carbonate ion. A distinction has been made between terms in the metal ion - carbonate ion interaction which have different physical origins, such as static coulomb interaction, short-range repulsion and electronic polarization. The additivity of the pair interaction is investigated in 3-body calculations. It is shown that for these 3-body systems pairwise addition of 2-body interactions from which polarization effects have been omitted is superior to pairwise addition of the full Hartree-Fock interactions. A model potential based on these modified interactions has been constructed. Results of MD simulations show that both structural and dynamical properties are well described by these pair potentials.